The SecureStick Magnet Lock-Lock Set contains four locks. When completely installed, the locks and key will penetrate over 1" of solid wood. This lock is completely invisible from the outside, but when the key is placed in front of the lock it unlocks it instantly. The lock also has a disenage feature, so that it can be 'turned off' in temporary situations. This set of locks should be purchased in addition to key or lock and key set - KidCo Item numbers S335 and S3362