I guess one of those metal locks like this one is unbreakable http://alt.coxnewsweb.com/shared-blo...ike%20lock.jpg but I guess it would be too short, and so places where you could attach it to might be limited.

If you like always having your trailer attached to your bike, could someone easily steal the trailer? Is there some special lock that could prevent people from stealing it? Should you detach the trailer and keep it at home?

Also what is the type of lock that locks in your wheels so that your wheels are safe? Does it take too long a time to lock the wheels in, by chance?