Sandbox Dual 15HR 40/80 grit These are "Dual Grit" belts for the FootPro Sandbox tools that have two grits instead of one. Using two different Zirconia coatings, it's easy to see the difference at a glance. One half of the belt length is finer than the other half. Packed in 10 piece boxes. Please note these belts are not for use on any power equipment.