It was a cable combination lock. Used many times before in the same area. I was actually dissuaded from getting a U lock by the people at the bike shop. I should have gotten one of those baby u locks to put on the rear tire a la vespas. FRUSTRATING. There were so many other bikes there secured by a shoestring and mine was locked according to instruction...gone, lock and all. I actually saw some broken pieces of someone else's combination lock on the ground. Guess I'm not the only person dealing with this BS.