These holesaws give safety, performance & cutting precision. They are for use in portable electric tools. They are hard enough to cut most materials used in mechanical workshops, shipbuilding, general maintainance etc, including metal & plastic tanks. Features include:- *HSS teeth beam welded onto a softer steel backing. * Very hard tooth tips (Rockwell 63 ). * Variable tooth pitch around the blade from 4 to 6 T.P.I. for faster cutting. *A thicker base plate, reducing vibration & allowing