The lower mounts are just 3/4" square aluminum tubing, the kind you get at Lowe's. The flanges on the lower mounts were cut off of a piece of aluminum "L" channel (I think it was 1 1/2"). The upper mount (the big square block) is made of laminated pieces of 1/4" ABS plastic, which I ordered from TAP Plastics. Those three small silver blocks that are between the upper and lower mounts are 1/4" aluminum. Those blocks act like keys, and fit into the three holes on the HT rack, so that the cases won't come loose even if they take a hard hit from below.
I don't often see the need to lock the cases to the bike, but if I do, I carry a couple Python cable locks in my top case. With those, I can both lock the case itself, and lock the case to the bike. They also come in handy for locking your helmet and jacket to the bike if you don't feel like carrying them with you.
"No matter where you go, there you are."
Last edited by RCinNC; 05-05-2014 at 10:18 AM.