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 armour or modular gear. 

Features:

• Mounts on mil-spec sized carbine receiver extension tube (not included) from manufacturers such as Colt, Armalite, S&W, LMT, and others (please see the note below)
  
• Two water-resistant battery storage tubes located on the left and right sides of the stock
  
• Each tube will store up to two (2) CR123A lithium or AA batteries
  
• Tubes are accessible from the rear in any stock position via a hand-removable rubber plug
  
• Supplemental friction lock minimizes accuracy robbing wobble*
  
• Premium chrome-silicon lock spring provides positive locking and long service life
  
• Sloping cheek weld provides a wide contact surface for user comfort
  
• Shielded release latch prevents snagging and accidental operation
  
• Replaceable 0.30" Rubber Butt-Pad offers an anti-slip surface and increases impact protection
  
• Compatible with Magpul ASAP®, ASAP® QD, and other receiver-mount sling attachments
  
• Sling Mounts
  
• Rear – Reversible Type 1 Sling Mount fits up to 1.5" push-button QD swivels (swivel not included)
  
• Rear/Bottom – 1.25" sling loops
  

 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:

* Friction lock performance may vary depending on the host receiver extension's dimensional tolerances.