2×36 In. 50x914mm Zirconia Cloth Sanding Belt. Price per pack of 10 Belts. Why Zirconia? Zirconia toughened AlOx adds about 15% Zirconium Dioxide to the Alumina which enhances the toughness between three to four times due to the reduction in fracturing. Less fracturing means the abrasive grain stays “sharp” for a lot longer.