The M-LOK Thumb Shelf is designed for octagonal M-LOK handguards or forends. It provides a repeatable reference point for a consistent shooting grip, gives the shooter's support hand thumb leverage against muzzle rise, and assists when braced against a barrier. The shelf is ambidextrous and features a ribbed, curved top for improved thumb contact during recoil, resulting in better muzzle control. It is molded from Magpul's proprietary polymer.