Material: The diamond hole saw bit is made of industrial-grade carbon steel, which is sharp and durable.15 sizes are available: 6mm, 8mm, 10mm, 12mm, 14mm, 16mm, 18mm, 20mm, 22mm, 25, 26mm, 28mm, 30mm, 40mm, 50mm.Application: Drilling all kinds of glass and light stone, such as diamond, ceramic tile, ceramic granite.Note: Decreasing the drilling speed, lowering the weight-on-bit and increasing the use of water lubrication will greatly extend the life of the drill bit.Warning: Not suitable for concrete or more than 1/2" in depth. Sufficient water is required for lubrication and cooling when drilling.Product DescriptionThe package includes:15PCS diamond drill bitUse suggestions:1. Water lubrication is required when drilling.2. Not suitable for concrete or the depth exceeds 1/2".3. Too high speed or pressure will cause burning.