Five double-ended carbon steel blades packaged in a reusable plastic container that safely stores and protects blades. When dull, the blades can be flipped over to reveal a fresh sharp edge. For use with most utility knives. The blades can be used for heavy-duty cutting on almost any material including boards, textiles, wire, some metals, leather, plastic, rubber, vinyl, rope and more. Made by Art Alternatives. Carbon steel construction Comes in a re-usable, matchbox-style case Compatible with most utility knives