Professionally installed by my builder's security subcontractor last year. Works great when it's working, but good luck when it's time to change the batteries. Followed the user manual exactly in the MULTIPLE INTRICATE steps required to reset and re-oriente the lock and add/delet/reset codes and it won't work. A rubik's cube is simplier. Calling a locksmith Monday, probably going to throw it in the trash and get a simple fool proof manual deadbolt. Another example of how technology only complicates our lives.