- The bits surface is coated with Titanium Nitride which is extremely hard and highly wear-resistant, therefore enhances the quality and extends the life of the product. - The Drill bit tip has a 135° split point geometry which ensures that there is no walking and slipping during operation. Bit Dia (D) (mm) / 5.0 Overall Length (L1) (mm) / 86 Working Length (L2) (mm) / 52 Per Pkg / 10