- Prevents HPA cylinder movement
- Improves nozzle alignment and air seal
- Compatible with all PolarStar engines
These precision shim sets are designed to secure an HPA cylinder firmly within the gearbox shell, preventing unwanted forward or backward movement during operation. Small variations in gearbox pin diameter between manufacturers mean cylinder conversion kits must allow enough clearance to fit the largest pins, which can sometimes result in movement when installed in gearboxes with smaller pins.
If the cylinder can shift under use, nozzle alignment can change, affecting how consistently BBs are seated into the hop unit. This can lead to reduced air seal, inconsistent FPS, and overall performance loss. By correctly spacing the cylinder to match your gearbox pin size, these shims help maintain proper nozzle position and consistent air delivery.
Available in multiple thicknesses to suit the most common gearbox pin diameters, these shim sets allow a more precise and secure fit across a wide range of replicas. They are fully compatible with all PolarStar cylinder conversion systems, including F2, F1, JACK, and Kythera engines. Read the full description for size compatibility.
- Durable 24 AWG wiring
- Nylon mesh protective sheath
- Compatible with REV2 and REV3 FCUs
The PolarStar Wire Harness is designed to provide reliable power delivery and long-term durability for PolarStar electro-pneumatic HPA systems. Constructed using 24 AWG wire, it offers strong electrical continuity to ensure consistent engine and FCU operation during use.
To protect the wiring as it passes through the replica’s body, the harness is wrapped in a nylon mesh sheath. This helps prevent abrasion and damage during installation or regular gameplay, particularly in tight gearbox and receiver spaces.
The harness is universally compatible with all PolarStar electro-pneumatic HPA systems that use a REV2 or REV3 FCU, excluding the original V2 GEN1 Fusion Engine and Amoeba kits. Multiple lengths are available to suit different gearbox types and installation layouts. Read the full description for the harness length guide.
- Mechanical HPA conversion for AEGs
- Easy installation - Everything included
- V2, V2.5 or V3 gearbox variants available
If you're a realism enjoyer becoming HPA-curious, this will convert you! The Kythera SA Mechanical HPA Engine Conversion Kit from PolarStar Airsoft is a mechanical HPA conversion kit designed as a drop-in replacement for the cylinder group of standard gearboxes. Choose your variant to match your chosen gearbox.
Being a mechanical system means you don't need a battery, don't need to avoid rain and get to enjoy the feel of a trigger system designed to simulate real steel single-stage triggers, complete with an authentic, tactile break and reset. This variant of the Kythera is locked to semi-automatic fire only, making it ideal for those who prefer a precise double-tap to a burst.
While you don't get the programmable trigger and electronic tuning options of the JACK™ or F2™ engines, the Kythera SA is ideal for milsim skirmishers looking for a leap in performance, DMR builders seeking the easy route to a reliable high FPS build or CQB specialists seeking a realistic yet incredibly snappy trigger. If you seek next-level performance and realism in equal measure, the PolarStar Kythera SA belongs in your build!
- Dual Solenoid HPA engine for AEGs
- Easy installation - Everything included
- For V2 (M4 / AR-15) or V3 (AK-47 / 74) gearboxes
If you're after HPA performance with professional-level tuning options, the PolarStar Airsoft F2™ HPA Engine Conversion Kit is the way to go! An updated version of PolarStar's incredible Fusion™ engine, the F2™ is a dual-solenoid engine, allowing tuning of both the loading speed and air volume via the included digital FCU (fire control unit).
The set is designed to drop into either a V2 (M4/AR-15) or V3 (AK-47/74) gearbox (depending on the variant you choose), including everything you need other than your airline, regulator, air bottle and FCU battery.
Offering a variable rate of fire up to a stunning 30 rounds per second, adjustable velocity and a vast range of programmable options, including alternative fire modes, anti-stiction mode, "closed bolt" mode and "AEG" mode, the F2™ engine is the right choice for experienced HPA users looking to move up to a more complex, high-performance engine. If this sounds like you, the F2™ HPA Engine Conversion Kit belongs in your build!
- Steel screws
- Original replacement set
- For Kythera SA - V2, V2.5, V3
If you've accidentally dropped a screw on the carpet monster and can't seem to find it, you're in luck! The PolarStar Airsoft Kythera SA Complete Screw Kit is a comprehensive screw replacement kit, ensuring you have spares in case of future disasters. The screws are made from steel.
This screw set is for the Kythera SA HPA Engine and covers the V2, V2.5 and V3 variants.
- For centreline F2™ HPA engine
- Full replacement O-ring set
- Perfect toolbox filler!
This is a full O-ring replacement set for the centreline version of the PolarStar Airsoft F2™ HPA Engine Conversion Kit. If you want to make sure all the seals are up to par, this is a great way to refresh them on the cheap. It's also a great bit of kit to keep in your toolbox just in case of an emergency, or you accidentally lose an o-ring during installation or maintenance.
- Flexible braided hose reduces kinking
- 36-inch length suits most setups
- Standard PolarStar HPA air line
The PolarStar Braided Air Line is a high-quality 36-inch HPA hose designed for reliable performance and unrestricted movement during play. It is made from flexible rubber and reinforced with a durable nylon braided outer sheath, which reduces the risk of kinking and twisting while allowing the line to move naturally with the player.
This air line is the standard hose supplied with PolarStar air rigs and is well-suited for most chest rig, belt, or backpack-mounted HPA tank setups. The braided construction adds additional strength without compromising flexibility and manoeuvrability, helping protect the line during aggressive/agile movement and long-term use.
It comes supplied with foster-style quick disconnect fittings pre-installed on the hose. The line is ready to integrate into most HPA systems. Please note that a separate male QD fitting for the engine or regulator may be required, depending on your setup.
- For Kythera™ SA HPA engine
- Full replacement O-ring set
- Perfect toolbox filler!
This is a full O-ring replacement set for all versions of the PolarStar Airsoft Kythera™ SA Mechanical HPA Engine Conversion Kit. If you want to make sure all the seals are up to par, this is a great way to refresh them on the cheap. It's also a great bit of kit to keep in your toolbox just in case of an emergency or you accidentally lose an o-ring during installation or maintenance.
- 12 Inch/30cm length
- Replacement original parts
- For PolarStar HPA Engines
Whether you've damaged your Input Airline or you're working on some home-brew HPA madness, the PolarStar Airsoft HPA AirLine Input Tubing, 6mm; 12" Length will come in handy! This replacement original PolarStar part is a simple airline with a 6mm outer diameter and 4mm inner diameter, an ideal replacement for a damaged input line for PolarStar HPA engines.
This section of tubing measures approximately 12 inches (30cm) in length, just the right amount to run from the engine to the externals of your build. Please note, this set only includes the airline and doesn't come with hardware or fittings.
- Built-in Motor Control Unit
- Programmable fire modes
- For JACK™, F2™, F1™ & Fusion™ HPA engines
If you're running an older FCU and want to update, the PolarStar Fire Control Unit for HPA Engine; Rev 3.3 is a superb option. Compatible with the PolarStar JACK™, F1™, F2™, Fusion Engine™, this is the latest iteration of the PolarStar FCU.
This digital FCU can be programmed for various fire mode settings and tuning options, including burst modes, anti-stiction mode, rate of fire adjustment and semi-auto limiter, to name but a few. Programming is super easy thanks to the built-in LCD screen and joystick, allowing you to adjust on the fly in seconds, should the need arise. The tuning options available depend on the HPA engine that will be used; check the user manual for more information.
The FCU is pre-wired to a mini-JST connector and requires a battery to function. We recommend an ASG 7.4V 250mAh LiPo, although the size of the battery you choose depends on the available space on your donor platform.
- Numbered sizing ensures a correct air seal
- For PolarStar Airsoft F2™ HPA engine
- Avoids manufacturer-specific inconsistencies
For PolarStar F2™ HPA engines, you need one of these PolarStar Airsoft F2Kythera Nozzles! They are sized using a numbered system rather than being labelled by rifle model. This is because nozzle length can vary between replicas of the same platform, depending on the manufacturer. Differences in gearbox shell thickness, hop unit positioning, or internal design can all affect how far the nozzle must reach to achieve a proper air seal.
To ensure the best possible compatibility, PolarStar produces a wide range of nozzle lengths. Each numbered nozzle corresponds to a specific overall length, and once you determine the correct number for your replica, that nozzle size is universal across all PolarStar HPA engines that use the numbered nozzle system. This means if your rifle requires a #1 nozzle, you will use a #1 nozzle regardless of whether you are installing an F2™, Jack™, or other compatible PolarStar engine. Some model-specific Kythera™ systems are excluded from this system.
Check out the "Full Description" for the replicas most commonly associated with the available nozzle sizes. These are guidelines only, as compatibility can extend beyond the models listed.
- Numbered sizing ensures a correct air seal
- For PolarStar Airsoft F2™ HPA engine
- Avoids manufacturer-specific inconsistencies
For PolarStar F2™ HPA engines, you need one of these PolarStar Airsoft F2Kythera Nozzles! They are sized using a numbered system rather than being labelled by rifle model. This is because nozzle length can vary between replicas of the same platform, depending on the manufacturer. Differences in gearbox shell thickness, hop unit positioning, or internal design can all affect how far the nozzle must reach to achieve a proper air seal.
To ensure the best possible compatibility, PolarStar produces a wide range of nozzle lengths. Each numbered nozzle corresponds to a specific overall length, and once you determine the correct number for your replica, that nozzle size is universal across all PolarStar HPA engines that use the numbered nozzle system. This means if your rifle requires a #1 nozzle, you will use a #1 nozzle regardless of whether you are installing an F2™, Jack™, or other compatible PolarStar engine. Some model-specific Kythera™ systems are excluded from this system.
Check out the "Full Description" for the replicas most commonly associated with the available nozzle sizes. These are guidelines only, as compatibility can extend beyond the models listed.
- Numbered sizing ensures a correct air seal
- For PolarStar Airsoft F2™ HPA engine
- Avoids manufacturer-specific inconsistencies
For PolarStar F2™ HPA engines, you need one of these PolarStar Airsoft F2Kythera Nozzles! They are sized using a numbered system rather than being labelled by rifle model. This is because nozzle length can vary between replicas of the same platform, depending on the manufacturer. Differences in gearbox shell thickness, hop unit positioning, or internal design can all affect how far the nozzle must reach to achieve a proper air seal.
To ensure the best possible compatibility, PolarStar produces a wide range of nozzle lengths. Each numbered nozzle corresponds to a specific overall length, and once you determine the correct number for your replica, that nozzle size is universal across all PolarStar HPA engines that use the numbered nozzle system. This means if your rifle requires a #1 nozzle, you will use a #1 nozzle regardless of whether you are installing an F2™, Jack™, or other compatible PolarStar engine. Some model-specific Kythera™ systems are excluded from this system.
Check out the "Full Description" for the replicas most commonly associated with the available nozzle sizes. These are guidelines only, as compatibility can extend beyond the models listed.
- Numbered sizing ensures a correct air seal
- For PolarStar Airsoft F2™ HPA engine
- Avoids manufacturer-specific inconsistencies
For PolarStar F2™ HPA engines, you need one of these PolarStar Airsoft F2Kythera Nozzles! They are sized using a numbered system rather than being labelled by rifle model. This is because nozzle length can vary between replicas of the same platform, depending on the manufacturer. Differences in gearbox shell thickness, hop unit positioning, or internal design can all affect how far the nozzle must reach to achieve a proper air seal.
To ensure the best possible compatibility, PolarStar produces a wide range of nozzle lengths. Each numbered nozzle corresponds to a specific overall length, and once you determine the correct number for your replica, that nozzle size is universal across all PolarStar HPA engines that use the numbered nozzle system. This means if your rifle requires a #1 nozzle, you will use a #1 nozzle regardless of whether you are installing an F2™, Jack™, or other compatible PolarStar engine. Some model-specific Kythera™ systems are excluded from this system.
Check out the "Full Description" for the replicas most commonly associated with the available nozzle sizes. These are guidelines only, as compatibility can extend beyond the models listed.
- Numbered sizing ensures a correct air seal
- For PolarStar Airsoft F2™ HPA engine
- Avoids manufacturer-specific inconsistencies
For PolarStar F2™ HPA engines, you need one of these PolarStar Airsoft F2Kythera Nozzles! They are sized using a numbered system rather than being labelled by rifle model. This is because nozzle length can vary between replicas of the same platform, depending on the manufacturer. Differences in gearbox shell thickness, hop unit positioning, or internal design can all affect how far the nozzle must reach to achieve a proper air seal.
To ensure the best possible compatibility, PolarStar produces a wide range of nozzle lengths. Each numbered nozzle corresponds to a specific overall length, and once you determine the correct number for your replica, that nozzle size is universal across all PolarStar HPA engines that use the numbered nozzle system. This means if your rifle requires a #1 nozzle, you will use a #1 nozzle regardless of whether you are installing an F2™, Jack™, or other compatible PolarStar engine. Some model-specific Kythera™ systems are excluded from this system.
Check out the "Full Description" for the replicas most commonly associated with the available nozzle sizes. These are guidelines only, as compatibility can extend beyond the models listed.
- Numbered sizing ensures a correct air seal
- For PolarStar Airsoft F2™ HPA engine
- Avoids manufacturer-specific inconsistencies
For PolarStar F2™ HPA engines, you need one of these PolarStar Airsoft F2Kythera Nozzles! They are sized using a numbered system rather than being labelled by rifle model. This is because nozzle length can vary between replicas of the same platform, depending on the manufacturer. Differences in gearbox shell thickness, hop unit positioning, or internal design can all affect how far the nozzle must reach to achieve a proper air seal.
To ensure the best possible compatibility, PolarStar produces a wide range of nozzle lengths. Each numbered nozzle corresponds to a specific overall length, and once you determine the correct number for your replica, that nozzle size is universal across all PolarStar HPA engines that use the numbered nozzle system. This means if your rifle requires a #1 nozzle, you will use a #1 nozzle regardless of whether you are installing an F2™, Jack™, or other compatible PolarStar engine. Some model-specific Kythera™ systems are excluded from this system.
Check out the "Full Description" for the replicas most commonly associated with the available nozzle sizes. These are guidelines only, as compatibility can extend beyond the models listed.
- Numbered sizing ensures a correct air seal
- For PolarStar Airsoft F2™ HPA engine
- Avoids manufacturer-specific inconsistencies
For PolarStar F2™ HPA engines, you need one of these PolarStar Airsoft F2Kythera Nozzles! They are sized using a numbered system rather than being labelled by rifle model. This is because nozzle length can vary between replicas of the same platform, depending on the manufacturer. Differences in gearbox shell thickness, hop unit positioning, or internal design can all affect how far the nozzle must reach to achieve a proper air seal.
To ensure the best possible compatibility, PolarStar produces a wide range of nozzle lengths. Each numbered nozzle corresponds to a specific overall length, and once you determine the correct number for your replica, that nozzle size is universal across all PolarStar HPA engines that use the numbered nozzle system. This means if your rifle requires a #1 nozzle, you will use a #1 nozzle regardless of whether you are installing an F2™, Jack™, or other compatible PolarStar engine. Some model-specific Kythera™ systems are excluded from this system.
Check out the "Full Description" for the replicas most commonly associated with the available nozzle sizes. These are guidelines only, as compatibility can extend beyond the models listed.
- For JACK™ HPA engine
- Full replacement O-ring set
- Perfect toolbox filler!
This is a full O-ring replacement set for all versions of the PolarStar Airsoft JACK™ HPA Engine Conversion Kit, excluding the variant specifically for SMG-7 platforms (MP7 styled replicas). If you want to make sure all the seals are up to par, this is a great way to refresh them on the cheap. It's also a great bit of kit to keep in your toolbox just in case of an emergency or you accidentally lose an o-ring during installation or maintenance.
- Protects seals and solenoids
- Integrated 80 micron air filter
- Foster 2 QD compatible
The PolarStar Filtered QD Fitting is designed to protect your HPA system from contamination, helping maintain consistent performance and long-term reliability. Filtering the air before it reaches your engine prevents dirt and debris from entering the system, where it could cause leaks, poor efficiency, or damage to internal components.
An integrated 80 micron filter element removes particles as small as 0.003 inches, roughly the diameter of a human hair. The conical filter design provides a larger surface area than traditional disc-style filters, allowing for strong airflow while still delivering effective filtration.
Manufactured from corrosion-resistant stainless steel, the QD fitting is built to withstand demanding environments and frequent use. It is compatible with industry-standard Foster 2 Series QD connectors, matching those used on PolarStar regulators and air lines.
Installation is quick and straightforward, with the fitting press fitting directly into standard 6mm nylon tubing used across PolarStar HPA systems. The filter element can be easily removed for cleaning and reused, and is fully replaceable if required.
- For PolarStar Micro Regulator™
- Full replacement O-ring set
- Perfect toolbox filler!
This is a full O-ring replacement set for all versions of the PolarStar Airsoft Micro Regulator™. If you want to make sure all the seals are up to par, this is a great way to refresh them on the cheap. It's also a great bit of kit to keep in your toolbox just in case of an emergency, or you accidentally lose an o-ring during installation or maintenance.
- Numbered sizing ensures a correct air seal
- For PolarStar Airsoft JACK™ HPA engine
- Avoids manufacturer-specific inconsistencies
For PolarStar JACK™ HPA engines, you need one of these PolarStar Airsoft JACK™ Nozzles! They are sized using a numbered system rather than being labelled by rifle model. This is because nozzle length can vary between replicas of the same platform, depending on the manufacturer. Differences in gearbox shell thickness, hop unit positioning, or internal design can all affect how far the nozzle must reach to achieve a proper air seal.
To ensure the best possible compatibility, PolarStar produces a wide range of nozzle lengths. Each numbered nozzle corresponds to a specific overall length, and once you determine the correct number for your replica, that nozzle size is universal across all PolarStar HPA engines that use the numbered nozzle system. This means if your rifle requires a #1 nozzle, you will use a #1 nozzle regardless of whether you are installing an F2™, Jack™, or other compatible PolarStar engine. Some model-specific Kythera™ systems are excluded from this system.
Check out the "Full Description" for the replicas most commonly associated with the available nozzle sizes. These are guidelines only, as compatibility can extend beyond the models listed.
- Numbered sizing ensures a correct air seal
- For PolarStar Airsoft JACK™ HPA engine
- Avoids manufacturer-specific inconsistencies
For PolarStar JACK™ HPA engines, you need one of these PolarStar Airsoft JACK™ Nozzles! They are sized using a numbered system rather than being labelled by rifle model. This is because nozzle length can vary between replicas of the same platform, depending on the manufacturer. Differences in gearbox shell thickness, hop unit positioning, or internal design can all affect how far the nozzle must reach to achieve a proper air seal.
To ensure the best possible compatibility, PolarStar produces a wide range of nozzle lengths. Each numbered nozzle corresponds to a specific overall length, and once you determine the correct number for your replica, that nozzle size is universal across all PolarStar HPA engines that use the numbered nozzle system. This means if your rifle requires a #1 nozzle, you will use a #1 nozzle regardless of whether you are installing an F2™, Jack™, or other compatible PolarStar engine. Some model-specific Kythera™ systems are excluded from this system.
Check out the "Full Description" for the replicas most commonly associated with the available nozzle sizes. These are guidelines only, as compatibility can extend beyond the models listed.
- Made from real buffer tube blanks
- Fuel your PolarStar HPA build on 12g CO2 bulbs
- For TM-spec M4 AEGs & PolarStar MP5K adapter
If you're sick of running an HPA bottle and line, the PolarStar Airsoft CGS™ Buffer Tube Type 2 for HPA Engine; 12g CO2 eliminates the need entirely! Designed to mount to Tokyo Marui-spec M4 AEGs (modifications required) and the PolarStar MP5K CO2 Stock Adapter, this buffer tube is made from real AR-15 buffer tube blanks, providing a superb quality finish made from the best materials for the job.
The CGS™ interfaces with the PolarStar JACK™, F2™, F1™ or Kythera HPA engines, allowing them to be fuelled using 12g CO2 bulbs. This means you don't need the usual air bottle, regulator and line setup, which can hinder mobility for fast-moving playstyles. If 12g isn't enough for you, add the 33g CO2 Insert to use 33g threaded CO2 bulbs, offering up to 500 shots per fill!
Designed for compatibility with Milspec AR-15 stocks and most M4/AR-15 AEG stocks, the buffer tube itself offers 6 adjustment positions to suit any body type or loadout. If you're stick of line snags and carrying an air bottle around, the CGS™ Buffer Tube from PolarStar will change your game!
- Insert for CGS™ Buffer tube
- Allows PolarStar HPA engines to use CO2
- Powered by 33g threaded CO2 bulbs (not included)
If you're running the PolarStar CGS™ Buffer Tube with your HPA build, the 33g CO2 Insert for PolarStar CGS™ Buffer Tube can up your firepower considerably! A conversion set designed for the PolarStar Gas Stock (known as the CGS™ Buffer Tube), this adapter replaces the 12g CO2 parts in the CGS™ buffer tube with parts designed for whopping 33g threaded CO2 bulbs, offering more shots before replacement while avoiding the need for an HPA bottle, airline and regulator.
Even if you don't have the CGS Buffer tube but still want to run CO2, you'll be happy to learn that the 33g CO2 Insert features standard ASA regulator threads and can be installed directly to your regulator, provided it is rated for 900 PSI.




















