Classic Army's Version 2, 7mm Type gearbox differs from other standard 6mm gearboxes in that the bushing holes are larger. These gearboxes are primarily designed for high-speed use in MP5's, however can also fit all MP5 (Except MP5K and PDW), M16, and G3 Series airsoft rifles.

Replacement Version 2 gearbox for SRC AEG.

Broken your stock Marui V2 gearbox? Looking to upgrade? In either case, you'll need one of these as a replacement!

UTG's gear box assembly for UTG M14 style airsoft rifles.  Also works with TSD Tactical M14 airsoft rifles.This product is the core gearbox assembly and includes all components inside the shell.  For replacement, additional disassembly is not required.

Matched Gearbox by Bravo Airsoft Heat-treatedPrecision 8mm Bearing wellsStandard Japanese 8mm Bearings 8x3x2.5mmHard-Coated with Trivalent Chromium (Cr III)Gearbox features high impact tolerance, durability, and strength making it perfect for your super high-speed and super high-FPS set ups.

Reinforced metal gearbox (Version II) For MP5/M16/G3 Series AEGs.

Echo 1 Complete replacement gearbox for the Echo 1 E90.

Echo1 M16 Complete Gearbox with MOSFET 7mm Reinforced Gear Box ,7mm Bearing ,Metal SPring Guide ,Metal Gear Set ,Metal Tooth Piston Body ,Alum. Cylnder ,Ported Polycarb Piston Head ,MOSFET LOW Resistance Wiring Harness (to the back/ M16 style) ,

The Echo 1 replacement gearbox for Echo 1 M4 style airsoft guns.  This is a complete gearbox, fully assembled to be a drop in replacement for repairing or upgrading your Echo 1 M4 or other front wired airsoft guns which are wired to the front and require a Version 2 gearbox.  *If you have any questions regarding this gearbox, please contact us prior to purchase.

The ICS Olympic Arms M120 Power Up Kit is a bore-up kit for your ICS M4 and M16 style airsoft rifles.  This kit includes everything you need to built an upgraded upper for your ICS rifle.  It contains the upper gearbox (MA34), an M120 spring (MC39), metal spring guide (MA46), tappet plate & spring (MA50), bolt (MP23), oversized piston head (MC56), aluminum piston (MC05), oversize 4-port cylinder (MC58).*CLEARANCE*