The Magpul M-LOK Thumb Shelf provides a compact, ergonomic indexing point designed to improve support-hand consistency and muzzle control. Molded from a durable black high-impact polymer, this low-profile shooting aid mounts directly to a single M-LOK slot to minimize rail footprint. It features a ribbed, curved top surface that maximizes thumb traction under heavy recoil, allowing shooters to apply steady downward pressure against muzzle rise. The completely ambidextrous design mounts seamlessly on either side of the firearm to accommodate both right- and left-handed shooting styles without modification. Optimized specifically for octagonal aluminum handguards, it serves as a rock-solid thumb-over-bore reference point or brace assistance option when running up against barriers. Magpul Black Polymer Thumb Shelf MAG1566-BLK