High quality: PCB series drill bits are made of high-quality tungsten carbide alloy steel, which is very wear-resistant, high hardness and anti-deterioration. The seismic design of the blade edge allows it to remain stable during engraving. Various sizes: 1/8" shank; bit diameter: 0.1mm, 0.2mm, 0 .3mm, 0.4mm, 0.5mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm, 1.0mm, 1.1mm, 1.2mm, 1 .3mm, 1.4mm, 1.5m, 1.6mm, 1.7mm, 1.8mm, 1.9mm, 2.0mm, 2.1mm, 2.2mm, 2.3mm, 2.4mm, 2, 5mm, 2.6mm, 2.7mm, 2.8mm, 2.9mm, 3.0mm. This set contains 30 bits of different sizes, each size having 1 piece. Advantage: With their cutting edge helical flute, these PCB drill bits can reduce cutting force and prevent drill bit breakage, while improving precision. They work quickly and cleanly, without any glitches or scraps. Application: Suitable for amber beeswax, circuit boards, cleaning 3D printer nozzles, plexiglass, bakelite, CNC engraving, jewelry, plastic and other precision drilling. Combination set of 30 Parts: There are 3 sets of drill bits (set A: 0.1mm-1.0mm; clearance B: 1.1mm-2.0mm; set C: 2.1mm-3.0mm), each of 10 pieces, and each set has a protective box. It is easy to store and transport.