This OLFA replacement rotary blade pack is made for 45 mm cutters used for quilting, sewing, and workshop craft projects. The set includes five 45 mm (1.77 in) blades so you can replace a dull edge during long cutting sessions or multi-layer work for accurate ruler-guided lines and repeatable pieces. Change blades with the cutter locked, keep spares covered and dry, and discard used blades in a secure container.