Mine are held closed with strong magnets, which connect to a steel plate that's glued in place (magnets won't stick to the aluminum, of course). The rivet (required) is fake, and the metal us cut away underneath it so it can open. So if you buy your belt boxes, be sure to ask that the two parts NOT be attached together, else getting them apart is going to be tough, once they're riveted in place.
The downside: Accurately sized belt boxes are too small for trading cards. But they're perfect for a key on one side, and ID/Credit card/cash on the other.