Material: Made of high-strength carbon steel with a nickel-plated surface for precise cutting. The drill tip is evenly coated with 80-grit diamond. Increase drilling speed Position Cutting: The hole saw with center drill offers center positioning that allows holes to be drilled precisely and quickly Swarf evacuation: Center holes and side holes help remove debris easily. The surface is nickel plated to extend service life and improve surface corrosion resistance Use: Suitable for drilling glass, marble, ceramic tile, block tank, glass fiber reinforced plastic tile, slate, granite, etc. Suitable for all electric drills and drillsdrums Note: Water lubrication is required when drilling. This can extend the life of the drill assembly. It is not suitable for concrete or objects less than 1/2 inch deep to avoid damaging the materialhighlighted and premature tool wear Size: 30mm Description: Material: High-strength carbon steel, nickel-plated surface, which can be cut precisely. The top of the crown is evenly set with 80 diamonds. Increase drill speed. Good design: The center guide hole and side hole can easily remove the drainage material and cover the surface with nickel to extend the service life and increase the surface corrosion resistance. p> Use: Diamond drill bits are suitable for hard surfaces such as glass, ceramic tile bottles, block glass, ceramics, marble slabs and perforated granite. Note: The hole diameter can be used for bevel cutting, circular gluing and subsequent right-hand drilling. Water must be lubricated when drilling. Diamond coated tools work best when cooled withWater propulsion tools. Package content: 1 hole saw.