8" Imperial Sanding Discs Resin Bond Paper F Weight A tough and durable aluminum oxide mineral bonded with a full heat resistant resin to a strong F weight backing. The backing provides excellent shelling and tear resistance, thus increasing the life and performance of the disc. Excellent for scratch refinement after coarse sanding. Discs are 8" in diameter with no hole. Requires disc adhesive. Sold in full rolls only. 50 discs per roll.