Use these Slice Ceramic Box Cutter Blades with the 10400, 10503, 10512, 10513, and 10514 Slice handles to cut boxboard or cardboard. Each blade is made from 100% zirconium oxide and has a finger-friendly double edge, which is sharp for materials but resistant to cutting skin. The blades have a rounded tip for safety, and they are non-conductive, non-magnetic, non-sparking, and chemically inert, so they will never rust. These oil- and lubricant-free blades come in a pack of four and are reversible, which doubles their lifespan.