Engineered for extreme durability and long life in hard metal applications. Designed with a variable helix that includes an aggressive 35 deg (degree) helix angle which ends at 15 deg. Cobalt bits with RED HELIX provide rapid chip removal limiting heat buildup to stay sharper longer. 135 deg split point tip delivers a precision start and prevents walking for fast, accurate holes. Ideal for tough applications. Applications include wood, stainless steel, metal, plastic, PVC (polyvinyl chloride). Sizes include 1/16", 5/64", 3/32", 7/64", 1/8", 9/64", 5/32", 3/16", 7/32", 1/4", 5/16", 3/8", 1/2".