OLFA-Endurance Rotary Blade Refill 60mm. The 60mm Endurance blade retains its cutting edge two times longer while cutting fabric before dulling. By applying innovative heat treatment and OLFA's proprietary sharpening process to tungsten steel, OLFA has created an exceptionally durable, high-performance cutting edge. Compatible with all OLFA 60mm handles. One blade per pack. Imported.