Quantity: 10pcs Color: Random Color Dimensions: Length: 38.1mm/1.5"; Edge Diameter: 0.7mm; Shank Diameter: Approx. 3.175mm; Box Size: 8.7 x 5.3cm/3.42 x 2.08" The drill bits are ideal for fine drilling of hard materials, for modeling, jewelry restoration, handwork, for PCB, SMT, CNC, mold, sculpture, plastic, copper, stainless steel The drill has a large chip removal space, which reduces the cutting force and the broken drill bit. The resistance is small and stable when removing chips, and the quality of the hole wall is improved. The PCB drill is easy to replace and can cut PCB solder holes well. Packed in an excellent storage container for easy access to what you need when you need it. These bits are made of high-quality materials and work well on printed circuit boards. Twisted tips and grooves will make drilling easier. Good quality product.