B5 Systems Rail Cover - M-Lok Black. The rail covers match the color and the shape of the rail at the top of the forearm. You won't have to worry about the cover slipping off the rail at the end of the day. Additionally with the strength of MLOK and the quality of the materials used this is a great way to finish off the top rail of your forearm. Add this cover to the end of your rail and rest easy knowing you have a quality cover that will last. Specifications for B5 Systems Rail Cover - M-Lok: Manufacturer: B5 Systems Length: 9 in Width: 1.75 in Weight: 5 oz Condition: New Quantity: 4 Pack Mount Type: M-LOK Country of Origin: USA Pack of 4 Heat and Chemical Resistant Press in Fit To 3 M-LOK Slots Package Contents: B5 Systems Rail Cover - M-Lok - B5 Systems RCM-1256: Rail Cover - M-Lok Black