STR Carbine Stock - Mil-Spec, RET, Black,
STR Carbine Stock - Mil-Spec, RET, Black,, The Magpul STR (Storage/Type Restricted) Carbine Stock - Mil-Spec is a drop-in replacement buttstock for AR15/M4 carbines using Mil-Spec sized receiver extension tubes. A storage-capable version of the CTR(R), the STR has improved cheek weld and two water resistant battery tubes on a compact, reinforced polymer A-frame design.