End Plate,Lower Receiver | 拖桿定位片
Fixed Receiver Extension Buffer Tube (M16A4 Style)|固定托托管(M16A4版)
UBR buffer tube | UBR 專用拖桿
Receiver Extension Tube Nut|托桿螺帽 (XM177用)
Receiver Extension Tube (Castle) Nut|托桿螺帽 (城堡環)
Recoil Spring (Soft)|覆進簧 (軟)