helps protect and secure your tarp when working with roll tarp systems. The roll tube is inserted into to the tarp pocket and then the tarp is screwed into the tube using the half moon clamps and self-drilling screws . U-clamps are sold in a pack of 12 With Screws .Plastic U-Clamp2" x 2" half moon clampAttaches to tarp using self-drilling screwsUse to attach tarp to roll tarp railPack of 12 with screws Dark Grey In color to blend in with straps ships to lower 48 states only these are exact replacement