This UHPPOTE Fail Secure Electric Latch Bolt Lock is perfect for wooden, metal, and glass doors. It is fail secure, meaning it is locked when power is removed. It has an induction distance of within 8mm/0.3in and an autolock time delay of 0/3/6/9 sec. The LED light indicates when the lock is locked or unlocked. It comes with a single side cylinder with a thumb for easy access. This lock is reliable and secure, perfect for any door.