The Black Widow 6-4008BW 4 in. Micro-Segmented Diamond Blade is a premier blade for fast, chip-and wobble-free wet/dry cutting of porcelain, marble, granite and ceramic tile. The unique micro-segmented laser cutouts around the perimeter keep the blade cooler for superior performance and a longer life. Independent testing has shown that Black Widow specialty blades continuously out perform the competition in durability for a longer life and speed of cut, reducing project time. Blade specifications: 7 mm Rim Height; 7/8-20mm-5/8 Arbor Size; 15000 Maximum RPM.