Norseman by Viking Drill and Tool 26443 4 Piece 9/16 in. to 1 in. Heavy Duty Black and Gold Vortex 1/2 in. Shank Set

Easily enlarges existing holes without damaging the point
Stay sharp up to 4x longer compared to conventional and other specialty tip design
Recommended for cast iron, brass, sheet metal, plastic, mild steel, copper, hardened steel
3-flats on shank
Made in the U.S.A