Zirconium/ Aluminum Oxide blendExcellent, economical choiceFast grindingAvailable 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 sandingBulk Spindle Packaging: Assures that each disc remains perfectly flat. The unique design offers the convenience of easy access and can be retightened to ensure that your discs are flat when you need them.Blue Line?âòÀÞ?â Packaging: Used for retail packaging in convenient smaller quantities. UPC bar coded.Custom Discs: All custom fiber discs are non-cancellable and non-returnableBacking Pads for Fiber Discs are available in Accessories