Master Lock DSNRN1003PBOX Nightwatch Combination Deadbolt with Bump Stop Cylinder, Bright Brass,Master Lock,DSNRN1003PBOX" /> Operates like any 3 digit dial combination lock, combines the keyed entry security of a deadbolt with the keyless flexibility of a safe lock Single cylinder deadbolt installs like a standard deadbolt with just a phillips screwdriver When the patent pending nightwatch feature is engaged, the lock cannot be opened from the outside, even with a duplicate key, it can only be engaged or disengaged from inside the house Six way adjustable latch 2-3/8-inch to 2-3/4-inch backset, square, radius and drive in latch face options Installs like a standard deadbolt with just a phillips screwdriver, exceeds ansi grade 2 specifications