Airsoft puška RK74-CQB

Indications v2, v3, v6 does not mean the level of advance, but only shape of gearbox skeleton which was used and selected by the manufacturer depending on the capabilities of the body of the replica. For example, a models of the M4/M16 family, MP5, have a v2 gearbox, while the AK family have gearbox v3.