The Magpul STR (Storage/Type Restricted) is a drop-in replacement buttstock for AR15/M4 carbines using mil-spec sized receiver extension tubes. A storage-capable version of the CTR®, the STR has improved cheek weld and two water resistant battery tubes on a compact, reinforced polymer A-frame design.
A shielded operation lever and supplemental friction locking system prevent accidental operation and minimize excessive stock movement for enhanced weapon stability and accuracy.* The STR incorporates two integral sling loops, a reversible push-button QD sling mount, and a replaceable 0.30" thick rubber butt-pad which provides positive shoulder purchase to prevent slippage even with body armor or modular gear.
 Made in U.S.A.
FEATURES
 NOTE: There are two basic sizes of M4 Carbine receiver extensions (buffer tubes): mil-spec and commercial-spec. If you have a commercial-spec extension on your rifle, make sure to order the Commercial-Spec STR.
SPECIFICATIONS**
STR Carbine Stock, Mil-Spec
* Friction lock performance may vary depending on the host receiver extension's dimensional tolerances.
** Specifications based on standard-length (flat-back) M4 Carbine receiver extension and may vary depending on tube manufacturer.