Breek Arms Plan B Sentinel Caged Flash Hider A closed-tine, fully shrouded flash hider engineered for superior flash suppression and reduced snagging on gear. Precision-machined from 4140 hardened steel and finished in nitride for long service life, the Sentinel delivers rock-solid alignment and a compact profile for mounts using the Plan B and Atlas interfaces. Overall length is 2.15 inch and the unit ships with a peel washer for consistent seating and repeatable engagement. The Sentinel provides an NVG-friendly signature reduction while preserving point of impact and reliable performance in demanding use. Note: Engineered for pin-and-weld installation on 14.5 inch barrels to achieve the 16 inch federal minimum barrel length.