The First Alert 2070AF Anti-Theft Wall Safe is perfect for concealing and securing your valuables and personal items. For protection, the safe features heavy duty welded steel construction, pry-resistant concealed hinges and 2 live door bolts. This expandable .33 - .85 cubic foot wall safe comes with 2 adjustable shelves to help maximize space and organize valuables and belongings. The wall safe is designed to fit standard wall-stud spacing and will expand to make use of a cavity depth ranging from 3 1/2 to 5 1/2 inches (2 in. x 4 in. studs or 2 in. x 6 in. studs). The safe is equipped with an electronic keypad lock which allows users to program a personal 3 to 8 digit passcode. Also included with the safe is an emergency override key which can be used to bypass the digital passcode in case of battery failure (4 AA batteries included).