1Use high quality materials and fine grinding process makes bit more sharp cutting edge 2Drill bit has a large scraps discharge space, little resistance and smoothly during the scraps discharge 3Reduce cutting force and broken drill, improve the quality of hole wall 4Easy to change out and do a great job cutting through the PCB for solder holes 5Come in a great storage container that is easy to grab the drill bit you need when you need it Description: These bits work fantastic on PCB boards.Sharp and twisted flute will make the drilling be more easy and effortless.They come in a easy-to-use plastic case with a holder for each bit.Drills bits are perfect for delicate drilling through hard materials for model engineering, jewelry repairs, craft work, suitable forPCB, SMT, CNC, mold, sculpture, plastic, copper, stainless steel. Features: Use high quality materials and fine grinding process makes bit more sharp cutting edge. Drill bit has a large scraps discharge space, little resistance and smoothly during the scraps discharge. Reduce cutting force and broken drill, improve the quality of hole wall. Easy to change out and do a great job cutting through the PCB for solder holes. Come in a great storage container that is easy to grab the drill bit you need when you need it. Specifications: Material:Tungsten Steel, White Steel Ring Color: Random Cutting Edge Diameter: 0.1mm, 0.2mm, 0.3mm, 0.4mm, 0.5mm, 0.7mm, 1.2mm, 1.3mm, 1.4mm(Optional) Shank Diameter: Approx 3.175mm Length: 38.1mm / 1.5" Box Size: 8.7 x 5.3cm / 3.42 x 2.08" Quantity: 10pcs per set Weight: 38g(approx.) Package Includes: 1 Set(10pcs) x Drill Bits Note: Due to different batches, color of rings might be different from the ones in picture.Please take the real one as standard.Thanks for your understanding.