Ergo Grip M-LOK WedgeLok, Rail Covers, 6 1/4X5/8, Slot Cover Grip, Dark Earth 4332-4PK-DE ERGO Grip's 7-Slot M-LOK WedgeLok Rail Covers (4-pack) improve your grip comfort and performance. The WedgeLok design snaps securely in place to eliminate movement or shifting of the grip panels. This provides you with a solid base to apply grip pressure on the forend without sacrificing comfort.