These safer chisel blades feature Slice's signature finger-friendly edge, which scrapes effectively but is safe to the touch. Because they're made of 100% zirconium oxide, they're non-conductive, non-magnetic, chemically inert, and will never rust. Slice advanced ceramic blades hold their edge up to 11-times longer than a comparable metal blade. Since they're double sided, each blade actually lasts up to 22-times longer than a single-edge metal chisel. Extra narrow for precision, these blades are ideal for artists, laboratories, electronics manufacturers, and more. The 10535 blades are compatible with Slice craft handles and replaceable-blade scalpel. Each package contains 4 blades.