When you're in the middle of a project, you don't want to lose time replacing your rotary blades. To keep your sewing or crafting on track, use the OLFA 45mm RB45H-1 Endurance (tm) Rotary Blade. This high-quality rotary blade is made of tungsten steel and hardened with OLFA's exclusive metal-strengthening process, which allows it to last twice as long as OLFA's standard rotary blades. Cut up to 1,500 yards of cotton fabric before the blade begins to dull. This OLFA Endurance™ blade cuts up to eight layers of fabric at a time, saving you precious time.