I love my street cuffs for places that make me nervous (like WalMart ). They weight 2.5 lbs!!! I lost my key once and had to leave my bike locked to the back of my truck for a week. I took it to two locksmiths and an auto mechanic that I know, all three of them said I was SOL, that the street cuff was impenetrable with anything they had. One of the locksmiths recommended I befriend a fireman, that the jaws of life should be able to cut it off.
(I found the key!)

http://www.masterlockcycle.com/product_9link.shtml