Replace Your Existing Lock—
this keypad/combination lock can be used to completely replace an existing deadbolt, latchbolt, or just a plain door knob. Just take off your existing door hardware and install this one in its place. It has been designed to retrofit easily on most doors (i.e., doors with a "standard prep").
Use with Your Existing Lock—you can also leave your existing lock in place and install this lock either above or below it for added security and convenience. If you do this, people who know your secret code will only be able to enter when both locks are unlocked, so you will have an extra layer of security and flexibility.