This device allows you to set your own secure code to activate doors or other machines you might want to lock. There are 9 numbers which means it is very secure. It is more secure than other redstone devices because it requires the user to set the code inside the machine with redstone. For the machine to function properly pick one number from each row for a passcode. Don't worry...that still makes 362, 880 of choices people have to guess at. If they do guess...well they might feel the urge to press the lock button which will keep them out until you unlock it yourself. There are signs telling you some details of the machine inside and out.