The MILWAUKEE® RED HELIX™ Cobalt 21/64 Drill Bit are engineered for extreme durability and longer life in hard metal applications. The Milwaukee Cobalt drill bits are designed with a VARIABLE HELIX ™ that includes an aggressive 35° Helix Angle which ends at 15°. The drill bits have QUADEDGE TIP™ to decrease heat buildup and drill faster. The 135° split point tip delivers a precision start and prevents walking for fast, accurate holes in Hard Metal, PVC and wood.The tapered drill bits feature a new ENHANCED TAPERED WEB™ that strengthens the bit's core to increase flute durability. The cobalt twist drill bits are ideal for tough applications, providing up to 15X life vs. Black Oxide Drill Bits™.