Features: - [High hardness]: M35 is made of cobalt-containing high-speed steel, with high hardness and strong wear resistance, specially made of stainless steel. - [Precision technology]: Precision grinding technology, smooth surface, high grinding precision. - [Sharp and durable]: 135-degree standard double back edge angle, fully ground drill, sharp and durable cutting edge, stable feed. - [Strong stability]: Universal round drill shank, widely used, clamping and tightening, not easy to fall. Specification: Produce name: Cobalt twist drill. Material: M35 high speed steel containing cobalt. Uses for: Widely used for perforating metal materials such as stainless steel, die steel, aluminum alloy, cast iron, copper, galvanized pipe, etc. Size: Drill diameter x Working length x Shank diameter x Total length. 5.2mm: 5.2mm x 52mm x 5.2mm x 86mm. 5.5mm: 5.5mm x 57mm x 5.5mm x 93mm. 6.0mm: 6.0mm x 57mm x 6.0mm x 93mm. 6.5mm: 6.5mm x 63mm x 6.5mm x 100mm. 6.8mm: 6.8mm x 69mm x 6.8mm x 109mm. 7.0mm: 7.0mm x 69mm x 7.0mm x 109mm. 7.5mm: 7.5mm x 69mm x 7.5mm x 109mm. 8.0mm: 8.0mm x 75mm x 8.0mm x 117mm. 8.5mm: 8.5mm x 75mm x 8.5mm x 117mm. Produce Included: 10 Pcs Similar-sized x Cobalt twist drill (The specifications you choose)