Specna Arms Complete Reinforced Gearbox V3 QD with Micro-Contact

Specna Arms
  • Quick change spring system
  • Complete replacement V3 gearbox for AK AEGs
  • Micro-switch trigger - Fast response, longer life

If you have an old AK AEG that needs a revamp, Specna Arms has just the thing! The Complete Reinforced Gearbox V3 boasts a wealth of pre-upgraded components, a quick change spring guide, and a microswitch trigger unit. If you aren't a fan of going inside gearboxes to solve issues this will suit you well as this version 3 gearbox is pre-built and ready to be installed in your AK AEG; all you need to add is a motor and motor cage!

Full description


The Specna Arms Complete Reinforced V3 Gearbox is designed for AK AEGs and is pre-built, meaning it needs minimal fiddling to be installed into your AK, and only needs a motor and motor cage. Perfect for those of us who would rather avoid messing around inside AEG internals!

This gearbox comes with some impressive pre-upgraded internals already inside, including an aluminium ball bearing piston head, aluminium cylinder head with a dampener, chrome aluminium low-friction cylinder, air seal nozzle and a metal ball bearing spring guide with QD functionality. To add strength to the shell, Specna has also reinforced certain areas which are known to be vulnerable, including the front end of the gearbox and the area around the cylinder window.

This gearbox replaces the legacy copper trigger contacts with a micro switch which gives the trigger a tactile and audible click, improves the trigger response and extends the lifespan of the trigger by improving electrical efficiency and avoiding the plague of electrical arcing causing corrosion to form, which is an inevitability with conventional copper trigger contacts. With a micro switch trigger, this gearbox should be well up to the task of providing a snappy trigger response with the bonus that a micro switch will need replacing less frequently as copper contacts, even if you skirmish in CQB with the prerequisite semi-auto spam!

The quick change spring system makes the gearbox easy to tune to meet your local site's FPS limit, and the pre-installed spring is an M110 which puts out around 400FPS. This spring will need switching for an M90/M100 to get it below 350FPS so we recommend grabbing an M90 or M100 spring if you don't already have one in your parts bin.


  • Reinforced alloy shell
  • Version 3 gearbox for AK AEGs
  • Quick change spring system
  • 8mm Bushings
  • Micro-switch trigger contacts
  • Alloy ball bearing spring guide
  • Aluminium type 0 cylinder
  • Aluminium ball bearing piston head
  • Aluminium cylinder head with dampening pad
  • Air seal nozzle with O-ring
  • M110 Spring pre-installed - 400-420 FPS approx.

Package Includes

  • Specna Arms Complete Reinforced Gearbox V3 QD with Micro-Contact



Internal Part Type
Complete Gearbox, Gearbox,
Patrol Base - Warning Icon
Patrol Base - Warning Icon
Parts Fitting
Name Variant
Rear Wired, Front Wired,

Weight and Dimension

Weight KG Icon
Weight (KG)
Approx. 0.537kg
Product Height
Approx. 9cm
Product Length
Approx. 17cm
Product Width
Approx. 2.7cm


Colour Wheel Greyscale
Item Colour
Construction Icon
Alloy gearbox shell and spring guide. Steel gears. Aluminium piston head, cylinder head and cylinder. Polymer piston, nozzle, tappet plate and selector plate.
Internal Part Construction
Polymer, Alloy, Steel, Aluminium, Spring Steel,

Part Specific

Part for Power Source Type
Weapon Platform
  • AK Platform
  • Long Gun
  • Assault Rifle
Package Includes
Complete Gearbox

Electric Part Specific

Gearbox Icon
Gearbox Version
V3 Gearbox
Gearbox Version Compatibility Variant
Version 3

Spring Specific

Spring Manafacturer Power Rating
Approx. M-110
Spring Approximate M/S
Approx. 110m/s, using 0.20g BB
Spring Approximate FPS
Approx. 400fps, using 0.20g BB

Bearing Specific

Spring Guide Bearings

Size guide

Parts Fitting

Upgrades and Downgrades should only be undertaken by experienced players, or Airsoft Technicians. Please note, changing any internal parts of a weapon voids its warranty unless done in-house by our staff. 

Please ensure that when fitting parts the part purchased is the correct part, as once a part has been fitted we cannot accept return.

We do know that players love to tinker, so we're here to give you help should you require it, and if needed you can get in touch with our workshop for more help!

Unique Parts

Please note that some parts may be unique to a specific brand of weapon. For example: Parts for an ASG M4A1 may not fit an ICS M4A1.

Parts from the same brand typically have a high chance of fitting, though be warned, some replicas use unique parts, so please ensure the part will fit before you attempt to fit it.

If you require help with fitting any parts feel free to get in touch with us via our Contact Us Page.