The belt is stocked with a bunch of mundane gear- throwing knives, flash-bang grenades, lock picks etc. Your basic modern ninja kit. But attached to the Belt as a foci you have some Aces. So, when you want, your special custom gear can give you a really powerful edge. Say just 1wd, but added to anything you use a piece of belt-gear to do for 4 Willpower.

Batman's smokebomb vanishing act makes more sense now- he's using his belt's Aces to boost a Stealth skill roll.