The F.A.B. Defense GL-CORE B is a high-performance AR-15/M4 buttstock designed to deliver unmatched fit, comfort, and maneuverability. Built from durable fiberglass reinforced polymer, it offers a lightweight, sleek profile with an integrated cheek rest and ergonomic rubberized butt-pad that enables quick shouldering and precise control across dynamic shooting scenarios. Its interchangeable buffer tube adapters ensure a tight, reliable fit on both Mil-Spec and Commercial buffer tubes, simplifying installation and reducing play for repeatable accuracy. The GL-COREs compact design minimizes snag risk thanks to its no-protruding-parts construction, while the inversed positioning lever helps prevent accidental release during active use. Dual integrated quick detach rear sling swivel connectors provide versatile, secure attachment options for a balanced carry and rapid reconfiguration on the fly. Ideal for precision practice, tactical training, and field deployments, this buttstock merges practical ergonomics with solid engineering, delivering consistent cheek height, shoulder comfort, and dependable performance under demanding conditions.