Irwin Tools 3 Piece Unibit HSS and Cobalt Drill Bit Set #1, #2 & #4. Irwin 15506SM Vise-Grip 3-Piece High-Speed Steel and Cobalt Unicity Bit Set Save time by eliminating the need to change drills when drilling round holes in thin materials. Each smaller size drill also acts as a pilot for the next size. Patented single-flute cutting edge gives greater control through steps and a true round hole every time. Durable titanium coating limits friction and provides longevity. Ideal for drilling holes into thin materials such as stainless steel, copper, brass, aluminum, plastic and laminates. Set contains #1 and #4 High Speed Steel Unbaits and an M35 grade Cobalt #2 Unicity. Laser-marked sizes on all bits. Speed Point tip penetrates faster than previous Unbaits and prevents walking. 3-faltted hex shank prevents slipping in drill chuck. #1 and #4 High Speed Steel Unibits. M35 Grade Cobalt #2 Unibit. Speed point tip for fast starting. #1 – 1/8″ – 1/2″. #2 – 3/16″ – 1/2″. #4 – 3/16 – 7/8. The item “New Irwin Tools 15506SM 3 Piece Unibit HSS and Cobalt Drill Bit Set #1, #2 & #4″ is in sale since Tuesday, April 14, 2015. This item is in the category “Home & Garden\Tools\Power Tools\Drill Bits”. The seller is “excell2255″ and is located in Richmond Hill, ON. This item can be shipped to Canada, United States.