Size Information: Our buffing wheels for grinders have a diameter of approximately 8 inches, with a center hole diameter of about 5/8 inches. They consist of 12 layers to better polishing effectiveness. Each aluminum polishing compound bar weighs 70 g / 2.5 ounces providing a comprehensive solution for your polishing and buffing needs Quality Material: These cutting buffing wheels are made from cloth of different densities: 1 blue airway buffing wheel (12 ply) for hard polishing, 1 orange airway buffing wheel (12 ply) for coarse polishing, 1 yellow airway buffing wheel (12 ply) for medium polishing, and 1 white airway buffing wheel (12 ply) for fine polishing. The wheels are designed for different purposes, and the center ring ensures durability for long-term use, providing longer and cooler operation compared to standard buffs. Recommended maximum RPM safety limit is 3000, Weight: 4.35853891974 Pounds, Manufacturer: tiyao