This 30-piece Flat Head Diamond Sand Drill Bits Set is built for reliable drilling on hard materials, featuring a diamond sand coating that delivers efficient cutting power for glass, ceramic, stone, jewelry, and metal. The 60-grit diamond sand texture balances speed and precision, making it suitable for both detailed crafts (like jewelry hole-drilling) and everyday DIY tasks.A standout feature is the flat head design: it creates steady contact with workpieces to reduce slippage, a must for avoiding damage to fragile materials like glass or ceramic. This stability ensures clean, controlled holes every time, whether working on tiny 1mm details or larger 2.5mm openings.The set includes 4 practical sizes to cover all common needs: 10 pieces of 1mm, 10 pieces of 2mm, 5 pieces of 1.5mm, and 5 pieces of 2.5mm. This range eliminates the hassle of switching between multiple sets, letting users tackle everything from delicate jewelry work to stone drilling with one package.Each bit has a 23.5mm shank that fits most standard rotary tools—no extra adapters needed, so users can start drilling right out of the package. The secure shank fit reduces wobbling, enhancing accuracy even with thin or brittle materials.Constructed with durable steel and a thick diamond sand coating, these bits resist wear and deformation. To extend their life, use water for cooling during operation (avoid dry drilling). With 30 pieces, replacing worn bits is simple, ensuring continuous access to reliable tools for crafts, DIY, and small-scale projects.Ideal for diamond drill bits for glass, ceramic, or stone applications, this set offers versatility, durability, and stability—perfect for DIY enthusiasts, crafters, and hobbyists.