This chain lock is just amazing! I was very impressed with how massive this thing is. Nothing, I mean NOTHING is cutting this thing off. You can read the details of the contruction on their web site. The key lock is easy to operate, it does seem to get stuck a bit, but the intructions say to wiggle or jiggle the key in place. So far, I have not have any problems. Just be careful though, because even though it comes with a protective covering, it may still scratch your bike. Not that it will, you just have to be careful with it because of its size and weight. So far I'm very happy with it and I got it for less $$ than at local stores. I'm also very happy I got the longer length, 64". The 44" one would have been too short.