Print all the bits. You may not need the backing if you are bolting to something very sturdy, but I was concerned that even with washers they might pull through the $5 ammo box I have. The latch spring needs to be a compression spring that fits close on a 6mm shaft. I found an expansion spring in the Harbor Freight spring kit #93323, stretched it to make it a compression spring and cut the length I wanted. To assemble the latch, put the spring over the shaft, compress it a bit, then fit the 2nd half of the latch holder and secure with #6x1/2" sheet metal screws. Attaching the sleds to your (whatever you are mounting) will be up to you, depending on what you're mounting. To attach the latch, slide the thing onto the rack, snap the latch over the end bar, then mark the position where the holes should be made in the thing. The latch is attached to the thing with #8 screws, whatever length you need, and #8 fender washers and #8 nylock nuts.