This OLFA replacement rotary blade pack is designed for 45 mm rotary cutters used to cut fabric, paper, and similar materials for crafts in the sewing room or studio. Ten 45 mm (1.77 in) blades are included to support frequent changes when cutting strips, borders, or repeated pattern pieces. Use the cutter's safety features during swaps, avoid touching the edge, and store unused blades in their case between projects.