FAB Defense GL-Core Survival Buttstock is a black polymer buttstock with a built-in AR 5.56 magazine carrier for AR-platform rifles, compatible with Mil-Spec and Commercial buffer tubes (tube not included) via interchangeable buffer tube adapters. Features an integrated cheek weld optimized for M4/AR15 platforms, a multi-textured rubber buttpad for secure shouldering during rapid fire, and ambidextrous QD rear sling swivel connectors. Compatible with all standard 5.56x45mm/.223 Remington AR15/M16/M4 steel magazines. Includes one Ultimag 10-round AR magazine. Safety note Follow all manufacturer installation instructions. Verify proper function and secure mounting before use. Comply with local firearm laws and regulations.