Smart question to ask. There is alot of junk on the market. I know, I've got a collection of junk locks.
It lasted maybe half a season. I tried another brand with similar technology. Same outcome. Either it stopped retracting or the stupid thing wouldn't lock anymore.
I suspect all the retractable locks have similar problems. I wouldn't buy one.
It didn't last but a few times. Cool idea but easily got crushed on a landing. Kinda flimsy. You could easily just break it off a snowboard rack.
This one is sorta bulky but it hasn't crapped out on me in four seasons. It's cheaper that the others too.
I found this one at Buckmans.com This picture makes it look extra huge but it is about 3 inches across when coiled up. It is
heavy and does fill up a pocket. When you don't know what base area you are going to be hanging around for lunch or apres board, it is an option to carry around.