Silicon carbide grainClosed coat structure for more material removal on various materialsRecessed center hole helps avoid scratching of the surfaceAvailable in Bulk or Blue Line?âòÀÞ?â Packaging, Resin over resin construction for a strong bond that is resistant to heat and moistureVulcanized fiber backing for heavy duty sandingAvailable in bulk and Blue Line?âòÀÞ?â packagingCustom Discs: All custom fiber discs are non-cancellable and non-returnableBacking Pads for Fiber Discs?Â?àare available in Accessories