Customer Rating: Summary: If you don't lose keys, it's OK Comment: This lock is well constructed, and easy to operate (though occasionally you have to fiddle with it a bit to get it to lock), but there's one potential issue that Master doesn't presently address. They have made no provision to supply spare keys. The type of key used is a new design that can't be cut on any commonly-available duplicating equipment, the blanks are not supplied, and Master stated to me that they do not make duplication service available from the factory either. As a result, if you need more than two keys, this is definitely not the lock for you. Kryptonite uses the same type of key, and will supply additional keys for Kryptonite locks for a reasonable charge upon request (you need the key code number from the head of the old key to order them), so it's obviously possible to supply replacement keys of this type, but Master won't do it.