Uses a special nut to fix the cap onto the stem. On to this special nut goes a smaller screw to hold the device specific bracket attachment. Others such as K-edge mount this bracket on to the cap, since the cap is plastic, it cracks.
Only caveat is the smaller screw needs a size 2.0 Allen bit. This is the smallest Allen bit and does not come w/ most all-in-1 tool. If you have complete allen key set you should be fine.