Product Description QEP 6-7008BW 7-Inch Black Widow Micro-Segmented Rim Diamond Blade, 5/8-Inch Arbor, Wet Cutting, 8730 Maximum RPM From the Manufacturer The Black Widow Diamond blades are designed for quick cutting of hard tile including porcelain, ceramic, granite and marble, without wobble or chipping. Independent lab test results have proven that Black Widow specialty blades continuously out perform the competition in durability for a longer life and speed of cut, reducing project time.