(This review was collected as part of a promotion.) The installation was relatively simple if you followed the instructions they included.  The unit takes 4 double A batteries.  Very easy to operate, full instructions are included.  You can program up to 25 entry codes.  The buttons light up which makes them easy to see in both day & night.  The audible tones are loud so you can hear them.  The unit comes with 2 keys to operate like a regular door lock.  This is a very nice looking deadbolt which offers great convenience!  I was given this lock for a review but we already had this installed at my primary residence.  I would purchase again!