Description: 1/8 Inch (3.175mm) Shank diameter, a must have for your CNC machines and any tool Includes 10PCS drill bits; also provides with 10 pieces of different sizes combo set such as "0.8-3.175mm" and "1.5-3.175mm" Made of tungsten steel, with high hardness, high wear resistance, high strength, resistance to bending, anti-impairment and long tool life Cutting edge strictly symmetrical: beneficial and efficient cutting, avoid offset drilling Great for Circuit Boards, Plastics, Fiberglass, Wood, Soft Metals, etc Specification: Material: Tungsten steel alloy Size Chart: Cutter Diam.: 0.8mm; Cutter length: 3.5mm Cutter Diam.: 0.9mm; Cutter length: 4.5mm Cutter Diam.: 1.0mm; Cutter length: 5.5mm Cutter Diam.: 1.1mm; Cutter length: 6.0mm Cutter Diam.: 1.2mm; Cutter length: 7mm Cutter Diam.: 1.3mm; Cutter length: 8mm Cutter Diam.: 1.4mm; Cutter length: 8mm Cutter Diam.: 1.5mm; Cutter length: 8mm Cutter Diam.: 1.6mm; Cutter length: 7mm Cutter Diam.: 1.8mm; Cutter length: 8mm Cutter Diam.: 2.0mm; Cutter length: 8mm Cutter Diam.: 2.4mm; Cutter length: 8mm Cutter Diam.: 2.5mm; Cutter length: 7mm Cutter Diam.: 3.0mm; Cutter length: 8mm Cutter Diam.: 3.175mm; Cutter length: 8mm Package Includes: 10 Pieces PCB Drill Bits Note: All dimensions are measured by hand, there may be small deviations. Color may vary slightly due to the color setting of each individual monitor.