Good for what they do - B5 Systems Rail Cover - M-Lok

4.5 inches soft rubber earthworm texture. These don't really lock in the mlok since they are soft rubber like the lopro ones lock. They sit up and give an earthworm sitting on the rail feel. No screw and no real lock leads me to believe these will be falling right out. They cover three slots so getting 4 of them is a little bit overkill.