The drill bit set includes 4pcs 6mm, 1pcs 8mm, 1pcs 10mm, 1pcs 12mm and 1pcs plastic box transparent. When drilling hard materials (glass, porcelain, marble, or granite), use high-pressure lubrication. water. High quality drill bits - Our drill bit sets are made from from hard and durable alloys, which are harder than ordinary drill bits. It also combines chips and drills, and the pointed design is more convenient to use. use, saves time and allows you to quickly drill holes. Drilling is smooth and has no broken edges. It will not cause tremors. Simple positioning can increase opening speed. 3 The flat shank can firmly and stably fix the drill bit in the drill bit. Versatility - The drill bit set is ideal for drilling holes in all materials including tile, tile granite, concrete, ceramic tile, bricks, wood, plastics, glass, masonry, etc. 100 percent - if you have any questions about the "drill", please contact us for a full refund or replacement. Whatever problems you encounter, please contact our after-sales service as soon as possible.