Spiral air-cooled backing pad for use with all types of Resin Fiber Discs Abrasive discs will last up to 10x longer Fits all popular brands of angle grinders Size : 5-inch 5 inch Backing Pads. Spiral air-cooled backing pad for use with all types of Resin Fiber Discs. Abrasive discs will last up to 10x longer.