Do you need to secure your things in a locker? Well, you're gonna need a lock. Like most everyone else, you'll probably get a combination lock like this one from Master Lock. Hopefully, you won't forget the three numbers that unlocks yours. The combination lock dials come in a rainbow of colors, if black is not your thing. They even make locks with a backup key entry, with letter combinations, and ones in which you choose your own code. Fancy.
Fun math fact: A lock combination isn't really a combination at all. It's a permutation. I guess permutation lock doesn't quite have the same ring to it, though, does it?