although the concept and operation of McGard wheel locks is wonderful, you are only issued a single(quite heavy) key upon buying the set of locks to attach to each car wheel to prevent its theft. woe betide the driver who misplaces it, thereby being unable to fix a flat etc. the website offers a spare key for $ 15. I would have thought that the price of the set, which runs $ 75 and above, would include a second back-up key. this is not the case. you can register your wheel locks on the site.