ebay

It ended up costing $40, $20 for the lock and the same for shipping. Took three weeks to arrive in Kansas(16 working days). The seller said it would take a min of 12 to the east coast and longer as you move west across the states. It is pretty cool, but $40 is a bit high. I can't imagine why these things arent available in the states at any LBS for about $20, they should be.

It relies on having braze ons on the back of the seat stays to attach, which I have never seen. It is pretty solid using cable ties, because it has three mount locations on each side, I put a cable tie through each of them. there are three short ties on each side and a long one on the top to hold it on, but the ties are pretty invisible when mounted.