MFC Sylvester Aluminum Fly Box Foam, Vibe X MFC's aluminum fly boxes are made from a durable, high-grade aluminum, which means they are light weight, yet extremely strong. MFC's digital printing technology creates a metallic, anodized effect, giving life to the image on the box. Features dual panels of soft, slit fly foam to securely hold your flies. 228 slots for flies - dries or nymphs. Hinged at side to open like a book. The right size to fit in your vest and wading jacket pockets. Dimensions: 6" x 3 1/2" x 1 5/16", Weight: 4.2 oz.