Product Number: 42945 Ceramic Grain 80 Grit Easy Grinding. Simply angle the backing edge against a hard metal to expose more flap material. Easier Heavy Duty Jobs. Stiff backing construction paired with a compacted 4 degree flap angle makes grinding easier, quieter and with less vibration. Trimming the backing allows for more of the disc to be used for fewer disc changes and better production rates. C3 - Self-sharpening ceramic grain and cool grinding aid. Ideal for hard-to-grind materials including steel and other heat sensitive materials. Pack of 25 discs