Special - while supplies last. We only have a few more of these in stock. 
These are stand-alone mechanical locks that need
no batteries.
Very cool lock works like a safe and is pretty heavy duty. Nightwatch combination deadbolt combines the keyed entry security of a deadbolt with the keyless flexibility of a safe lock. Operates like any dial combination lock. Provides combination backup for those who prefer keyed access for daily use. Fits standard BHMA deadbolt door preparation. Features Master Locks exclusive BumpStop Advanced Cylinder Technology virtually bump proof and pick proof. Replaces any standard residential deadbolt. Exceeds ANSI Grade 2 Standards. Available exclusively from Master Lock.

No battery needed for these locks!
Important - Please note: the combination on this lock can only be changed by a locksmith. Master suggests that the end user not attempt to change the combination.
Operates like any 3-digit combination lock.
Combines the keyed entry security of a deadbolt with the keyless flexibility of a safe lock.
Provides combo back up for those who prefer keyed access for daily use.
When Night Watch features is engaged, the lock cannot be opened from the outside. Even with a duplicate key.
The Night Watch features can only be engaged or disengagedfrom inside the house.
The Night Watch cylinder cannot be PICKED or BUMPED.
Exceeds ANSI Grade 2 speifications.
Adjustable latch: 2-3/8" to 2-3/4" backsets.
Anti-pry collarresists prying, simplifies installation.
Dimensions: 3.1 x 4.1 x 4.6 inches
Please note that to change the combination on this lock the manufacturer suggests that the lock be taken to a locksmith.