The quickest, strongest way to mount your RotopaX. Use with included base plate or remove the plate to attach the mount direct by bolting up through the bottom or down through the top. The unique design adds strength and provides extra tightening power. Pack Mounts are milled from solid aluminum then anodized black and finally engraved. This mount uses a 5/16" steel all-thread rod with a steel threaded insert (Helicoil) in the base.These are not cheap injection molded plastic parts that will fail when you are 25 miles down the trail!