BREEK ARMS PLAN B SENTINEL 30 CALIBER CAGED FLASH HIDER The Sentinel is a closed-tine, fully shrouded design for superior flash suppression and to reduce snagging on gear. Built for Plan B mounts and pin-and-weld builds, it delivers rock-solid alignment, compact length, and NVG-friendly signature reduction. SPECS Weight: 1.8 oz. Overall Length: 2.15 Material: 4140 Hardened Steel, Nitride Thread Pitch: 5/8 x 24 TPI Caliber: .30 CAL Fast attach for Plan B suppressor mounts Engineered to be pinned & welded on 14.5"" barrels to meet the 16" Federal minimum length requirement Mfg: Breek Arms