The Milwaukee Metric HSS-G THUNDERWEB Metal Drill Bit design is unique, with a conical shaped web which gets thicker towards the back of the drill bit. It has a parabolic web cross section that gives a larger web thickness, increasing the strength of the bit and prevents breakage. The THUNDERWEB flute form ejects hot chips rapidly, dissipating heat better, increasing the life span and working time. The open flute form also reduces drill drawback, especially when drilling deeper holes. The 135 split point allows for precision starting, quick penetration, and requires less effort and feed pressure, and is perfect for drilling very hard materials. They are also great for drilling on curved surfaces. This Milwaukee HSS-G THUNDERWEB Metal Drill Bit has the following specification: Diameter: 12.0mm Working Length: 101mm Overall Length: 151mm Pack Size: 1