SIERRA 316L Optic Ready - MLOK R4 (1x9) has a Free-float 15-inch rail featuring MLOK slots on eight sides, positioned horizontally at 3, 6, and 9 o'clock, and slanted at 1:30, 4:30, 7:30, and 10:30 positions. The top (12 o'clock) includes MLOK slots along three-quarters of its length, transitioning to a Picatinny rail near the muzzle for mounting options like a front sight, laser, or weapon light.