Small diameter drill bits, for drilling components lead wire holes in printed circuit boards Suitable for drilling plastic, soft media, circuit board, wood or metal (aluminum, copper, e.g.) Ideal for model engineering, electronics and jewelry making, etc Tungsten steel blade, welded iron body 10pcs drill bits can be used for your plastic, wood, or metal (such as aluminum or copper milling). PCB drill bits are designed for CNC / PCB milling machine for precise milling. Cutting Edge Diameter: Approx. 0.5mm Cutting Edge Length: Approx. 10mm Shank Diameter: Approx. 3.1mm Overall Length: Approx. 38mm Package Includes: 10 x Drill bits Note:Light shooting and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.