SUNJOYCO 4 Inch Diamond Cup Grinding Wheel 12 Segments Heavy Duty Turbo Row Concrete Grinding Wheel for Angle Grinder, Granite, Stone, Marble, Masonry, ConcreteWarm Tips:Please check the size of the wheel to see if they can compatible with your gender! If do not fit your gender or do not know how to use, we are willing to offer you help.Specification:Material: HHSProduction process: sinteringColor: GoldOuter diameter: 100 mm /4 inchesInner hole diameter: 20mm / 0.79 inches (without metal ring)Inner hole diameter: 16mm / 0.63 inches (with metal ring)Thickness: 5 mm / 0.2 inchNot threadedHow to Use It Properly?1. Strictly follow the instructions in the machine manual.2. Do not install a diamond dish/cup wheel that is too loose or too tight on the flange.3. Tighten only with the tool provided with the machine.4. Be sure to hold the wheels properly to prevent slipping, but do not use excessive force. Never use a hammer.5. Keep flanges and threads clean without burrs and rust.6. Before installing the wheel, please replace the deformed or damaged flange.Please protect yourself when start cutting!We recommend the following personal protective equipment:Eye protectionEar protection (earmuffs)Hand protection (gloves)Lung protection (dust mask)Important note:1. Never remove the machine's protective cover and make sure it is properly adjusted to keep debris away from you.2. Make sure that no one else is in danger, especially near the machine while working.Package Included:1 x 4-inch diamond concrete grinding wheel