The Victorinox orange peeler is found on a few 2 1/4" (58mm) Swiss Army knives. It's a small tool with a notch and a sharp edge on the inside side of the notch, which slices when you pull on the tool.
Uses: The peeler tool works extremely well for peeling oranges-- just poke it under the orange rind, and pull it along to slice the rind without cutting the orange itself.
The peeler is surprisingly useful for various random tasks that no other blade can handle, and it would sure be great if Victorinox added a similar "back-blade" tool to the bigger knives (maybe instead of the hook, hint hint).