I ordered this to replace a standard keyed front door handle. Installation was easy, it fits into the existing cuts in the door and frame. Getting the wiring from the keypad through the door and plugged in to the rear interior panel battery compartment took a couple of tries, but worked fine. They could give a little more slack in the wiring. I didn't use either of the strike plates (square and rounded), just used the existing chrome plate. Programming the keypad is easy, and seems very secure. You can change the default programming code string to whatever you want if you want to be extra safe. It will hold quite a few different 4 digit codes, which is nice to have options in case you forget one, and so you wear the keypad more evenly (don't want just 4 numbers worn down). It comes with a single key to manually open the latch if the battery dies or the unit fails. So far I haven't needed it.As for operation, this thing is great. Mine sits on a south western facing door that gets full sunlight all afternoon. It has been pushing 100 degrees F for weeks, and works just fine. I am on my 4th month of use, and the original 9 volt still runs it fine. I think they recommend changing it once a year on the same schedule as your smoke alarm. It is so nice to be able to step out for a walk or jog and leave the keys at home. You can text a code to friends and family if they need to get in while you are away. You can put in a code for a day if you need to let in a worker, and then delete it when they are done. No fumbling for keys when you have an arm load of groceries. I like that it is keypad only, no blue tooth or wireless access to make it vulnerable to remote tampering.I paired this with a standard keyed deadbolt of the same design and manufacture just to have that added, unhackable backup for when I am asleep at night or away for long periods.If you are on the edge about buying this thing, just do it. You will love it.And I paid full price with my own d*** money, no discounts or review bribes!*edit*So it's been three years now, and this lock and keypad works as well now as the day I bought it. The battery gets changed once per year, and has not gone dead on me yet. Haven't needed to use the backup key once. I've seen some complaints of the finish coming off, but have had no such issues. Perhaps newer units had a bad batch? Mine still looks brand new, though it is behind a glass screen door, perhaps that saves it from UV damage. Heat, on the other hand, is extreme behind that greenhouse glass. The front of my home gets extremely hot in the summer, weeks at a time in the 90s and 100s, and it has had no issues. The keys and numerals on them still look perfectly new. The digits seem to be embedded inside the rubber or silicone buttons, and have not faded or worn at all.Still extremely happy with the purchase.