This key when entered into a Kwikset KW1 Lock will bind the lock and not allow the lock to be reused unless the lock is disassembled or the person is a mastermind at removing the key. The pins will fall into the groove and because their is no ramp for the pins to slide back up on, the key becomes stuck in the lock. Although it is possible for a mastermind or locksmith with some talent to remove this, the common person wouldnt be able too. These are good for locksmiths, landlords, and businesses that need to keep people out. However once used, the key is stuck in the lock and can't be reused. The key can also be broken off in the lock due to the craftsmanship of the key.