C&F Design fly boxes are the only ones in the world with patented Micro-Slit Foam, the best way to store flies. No other system takes such great care of every aspect, from hook to hackle. Just slide the hooks along slits of the foam, and the foam grabs the bend of the hook, securing barbed and barbless flies alike with a snug but gentle fit that always stays in place. Hooks stay straight and flies won't mat.