Thin metal cutters produce infinitely more accurate holes than common bi-metal hole saws. Designed for use with hand held drilling equipment, these cutters drill up to three times faster than holesaws and have superior tool life. Centerfree design eliminates deflection and leaves smooth bore in work piece. Provided arbor system quickly installs to most hand drills, accepting a full range of cutters. Ideal for HVAC, electrical and maintenance contractors.