King Arms 6mm Gear Box for Marui AK/G36 Series APS II Keymod is the name given

Keymod is the name given to a universal interface system for firearm accessory components in an effort to establish a system superior to the MIL-STD-1913 accessory rails currently in use

thus improving long term durability

and the CCP

Rear magazine loading allowing longer barrel length (~470mm)

King Arms 6mm Gear Box for Marui AK/G36 Series APS II Keymod is the name givenEssential part for upgrading your Airsoft Electric Gun AEG Version III Bare Gearbox To build a tight & durable Gearbox Anti Heat & Anti Wearing Construction Suitable for Marui AK G36 Series Airsoft Electric Gun AEG Rifle Silver Color As always, upgrading AEG require necessary skill & technique to dissemble the gearbox, consult expertise if needed SKU KA GB 01 Item Weight (gram) 259 Major Color Silver Built Material Aluminum Manufacturer King Arms