ITEM NAME:0.8mm Tungsten Steel Micro Carbide Engraving Drill Bit PCB For X10 PC GFE 0.8mm Tungsten Steel Micro Car.10pcs 3.175mm Tungsten Steel Milling Cutter Bits End Mills for Drill Hole. Material:Hard alloy (tungsten steel). Bit chip space is large: small chip resistance, smooth, little heater of drill, reduce pollution of drill;.