When this arrived I couldn't believe how heavy the small box was.  The directions were very easy to follow and it didn't take long at all to install and get set up.  This lock definitely gives me an extra sense of security. It notifies me when my door is locked or unlocked.  I also like that I can add different codes for a defined period of time.  If I need to let a family member in, I can set a code for a few hours. Best of all,  I dont have to worry about losing a key.