The OLFA RB18-2 is a set of replacement rotary blades for small detail cutting in quilting, sewing, scrapbooking, and general crafts. The pack includes two 18 mm stainless steel blades for use with OLFA RTY-4 and OLFA CMP-3 tools, and each blade arrives in a protective case. Store blades in the plastic case between uses, install carefully to avoid nicks, and replace as soon as cutting becomes difficult or ragged.