NTOA (National Tactical Officers Association) tested and recommended.Six-position collapsible stock with rubber non-slip recoil pad and skeletonized design features a Picatinny rail and storage compartment for CR123 batteries (4 total) or other small items. Ambidextrous design is easily achieved by switching the battery compartment lid and Picatinny rail. Two ultrasonically welded metal inserts allow for the addition of optional quick release sling adapters (PBSS).• Ambidextrous side snap-tight latch compartment provides storage for 4 CR123 batteries• Side Picatinny rail allows addition of Adjustable Cheek Piece (ACP) or Mag Holder (MPS)• Rubber non-slip buttpad with tapered angle, allows faster shouldering and increased comfort with body armor• 2 ultrasonically welded metal quick release sling mount pointsAvailable with tube assembly: buffer tube, buffer, buffer spring, lock nut and latch plate.