ERGO Modular Wedgelok Rail Covers 4-Pack Black B. These Rail Covers developed by ERGO are resistant to chemicals and heat to provide many years of reliable use. Each of these low-profile Ergo Grip 6.25in M-LOK Wedgelok Slot Covers features a positive non-slip aggressive texture that provides an ergonomic grip at all times. Add some extra grip to your weapon with the help of these Ergo Grip M-LOK Wedgelok Rail Covers - 4 Pack. Specifications for ERGO Modular Wedgelok Rail Covers: Manufacturer: ERGO Fabric/Material: Rubber Length: 6.25 in Width: 0.625 in Mount Type: M-LOK Features of ERGO Modular Wedgelok Rail Covers 6 1/4in long and 5/8in wide Covers 4 M-LOK Compatible slots Low Profile and can be cut to fit fewer slots Package Contents: ERGO Modular Wedgelok Rail Covers ERGO 4332-4PK-BK-B: Modular Wedgelok Rail Covers 4-Pack Black