Dremel 12-Pack 1-1/2" Reinforced Cut-Off Wheels are designed for cutting metal and plastic. They are made with fiberglass backing and have a 1/8" arbor size. They are compatible with all Dremel rotary tools and have a speed rating of 30,000 rpm. The DREMEL EZ LockTM makes accessory changes easy as pull - twist - release. The one-piece mandrel design simplifies the process of changing cutting wheels and makes it easy to cut through metal.