Bolts to the side of Knight's Armament URX 3 and 3.1 rails.
-Made of Plastic, also available in Aluminum (part number 30412-ALU)
-Overall length: 3 inches
-Thickness is 0.250" so it will not match up with the build in rail sections of the URX, it will sit slightly higher.
Note: Flat Dark Earth is made to closely match Magpul FDE