The 55L Rigid Mount is a hard-mounted system designed to be able to mount a 55L Rugged Case to your roof rack or anything with mounting capability. Its design allows the mount to shoehorn into the tie-down channels of the 55L Rugged Case andhas 1/4″ holes tobolt down to your rack or flat surface. The mounts are .188 black powder-coated steel. *Mounting hardware not included*