The KM4 Series complete upper receiver has the forward assist button and ejector port door preassembled, and also comes with the charging handle and mock bolt plate. This piece fits all KM4 Series except for the new KM4 KR series, which means it is compatible with all SR, CQR, and Battle Rifle AEGs, as well as the KM4A1 and the Commando.

Weight .62 lbs
Dimensions 8 × 1.5 × 2.5 in