After the batteries were inserted himself has programmed a code, and the first things in front of his little sister hidden / locked away the little one (8 years). There are four numeric buttons (ie 1-4) available to program a 4-digit code. So there is enough for the time being possible combinations without being too complicated.
If you forget the code or want to program a new, there is a fairly hidden and recessed button that must be pressed.
The vault is stable and big enough, the electrical opening and closing works flawlessly and it's always an interesting toy.