... duration and even 2 time than normal drills. HSS Double Ended Drill Bits, ISO CERTIFICATED Product Description: HSS ... Drill Bits, Double Ended Fully Ground 4341,9341,M2,M35,M42 3 ... 6.5mm White, TIN Coated, Rainbow Color, Bright, Black & Bright, Zirconium Coating, Black, Coffee Color, etc. 118°or 135° * ... sheet, sheet brass, sheet aluminum and plastic sheets.