Amazed @ quality & ease of installation.  I'm a woman in mid 70's, & this is my VERY FIRST attempt @ installing ANY lock anywhere.  The directions looked too challenging @first, however, after reading over them once, I tackeled the project & only needed to call "help line" @ the very end when I was unable 2 put battery cover on.  A quick call 4 help, loosening 2 screws, & the cover went easily over batteries.  INCREDIBLY, THE LOCK WORKS PERFECTLY ---- yep, a supposedly over the hill very senior lady actually succeeded @ what seemed a daunting task!  Wish u could have seen my shocked expression when, after entering the code, the lock  performed perfectly.  Icould not b more pleased!!!!!