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 adaptors (PBSS).

Includes:
buffer tube
buffer spring
buffer assembly
nut and collar