H119 Bi-Metal Holesaw Impact Sutton Tools Impact Bi-Metal Hole saw are designed for use in impact drivers. Suited to cut sheet metal up to 3mm maximum thickness. Ideal for electrical installation, junction boxes, ducting and general sheet fabrication. 1/4" Hex shank suitable for impact drivers Ejector spring quickly ejects waste material Thin wall 8 TPI for fast and burr free cutting Stop shoulder to prevent over drilling Bi-Metal HSS premium quality for toughness and longer life Technical Specs: Diameter 20mm