Safety Wire
I've never trusted mine as it came off one time on a semi-rough road and bounced. I use a safety wire, wired to one of the case screws and one around the mount. Each has a loop on the end and I pass a bolt with a wingnut thru the two loops so I can still quickly take the case off if need be. I just don't trust the clamp thing. The case was used and the mount is new, as is the clamping/hook mechanism. When I bought the case it looked new, but now has some minor cosmetic damage from the ejection. That's what stickers are for, right? I also have a bungy wrapped around it, which is holding on a Volvo headrest that acts as a backrest for my pillion, when I have one. It acts as a second failsafe and passengers seem to like it. The gray matches the TT seat too.