Designed to be used with natural feathers, wing sheet material, foam & other synthetic materials. Handmade in Montana with sharpened razor stainless-steel blades, beautifully grained wood with a hand rubbed Danish oil finish. One set of blades makes 100s and 100s of bodies or wings. Sizes: (Lg 2-4), (Med 6-8) or (Small 10-12) (SPECIFY SZ) or Set of 3 with matching tool caddy