【X-SHAPED HEAD】: It features an innovative X-shaped geometry with a unique cross-spline design for optimal disassembly and ease of use. Fully hardened drill with double fluted spiral for efficient waste removal. 【SET OF 7 CONCRETE DRILLS】: 4mm. 5mm. 6mm. 6mm. 8mm. 10mm.12mm*160mm; The drilling depth is 100mm. This allows you to drill all common bolt holes. (For the safety of your machine and yourself, the use of a three-prong impact drill is not recommended.) 【CARBIDE DRILLS】The drill bit set is made of high quality carbide steel, durable and rust resistant. The tungsten carbide tipped drill head is harder, stronger and more resistant to extreme loads; high density drilling and fast waste disposal 【2-HOLE shaft】: Round handle, two-hole drill, normal drilling tools in individual red box for concrete, granite, stone. It ensures optimal and more efficient removal of dust and dirt through the rounded spiral geometry. 【APPLICATION】: Suitable for drilling holes in concrete, ceramic tiles,