Dura-Grit AbrasivesTough tungsten-carbide cutters for tough jobs. Very agressive yet leave quite a smooth finish. We rate them between a Ruby Carver and a Typhoon bur. They are very controllable and they last and last. Grit will not tear loose and the edges stay sharp. All have 1/8" shanks. Most DuraGRIT cutters are available in your choice of several grits.