Single Cylinder Deadbolts are the most common deadbolt type and are generally used in combination with a keyed door knob or lever handle on exterior doors.Single cylinder deadbolts require a key to unlock and lock the door from the outside. From the inside the door can be locked or unlocked with a simply turning the thumb turn mechanism.

See Also: Double Cylinder Deadbolts | Keyless Deadbolts | Single Sided Deadbolts