The OLFA Fabric Cutting Kit includes a 45mm Quick-Change Rotary Cutter and a 12" x 18" Double-sided, Self-Healing Rotary Mat. OLFA self-healing rotary cutting mats should always be used to avoid damage to your work surface, and extend your blade life. The RTY-2/CYEL (45mm) uses OLFA 45mm replacement blades, which cut up to 8 layers of cotton fabric.