The OLFA RB45-1 is a replacement rotary blade for common 45 mm rotary cutter handles used in quilting, sewing, and general craft cutting. It is a tungsten steel blade sold as a single blade in a storage case and is compatible with most OLFA 45 mm rotary cutters for quick replacement. Use on a self-healing rotary mat, handle the edge carefully during installation, and replace promptly once cutting resistance increases.