Got this for an exterior gate. So I read the reviews and realized that all the bad reviews were mostly about instructions and fitment. Yeah, instructions are horrible. If you have ever installed a door knob, then you don't need the instructions. The code set is very straightforward. It comes blank and you just turn the screw on the digit you want as a code. 1234, 2143, 4321 1432, etc are all the same code. Its mechanical and not in sequence. Yes, doors are all different thicknesses and it comes with 4 different length shafts to try to accommodate most. If your door falls in between sizes, you can either return it, leave a bad review and get back to your latte or you can pick up a hack saw and trim a little off the closest shaft size. My handle has gone through rain and my gate swelling and getting stuck against the jambs where I have to really pull on the handle to get it open. It is still solid. I am very happy with this and glad I no longer have to replace batteries.