100% Cloth ??? Belt Sander Paper PRO: Sanding belts are crafted with selected premium open coat aluminum oxide grain, feature excellent abrasion resistance, anti-static and anti-clogging. No such "A lot of fall out of the grits and fiber" occurred in normal use. ??? Strong Connection at the Seam???Sanding belts' thoughtfully diagonal lap splice minimize bulges at the joints to maximize the strength of seam connection for a smoother experience and less "belts coming apart" issue, compared to other similar products. ??? Max Performance: Sander belts works perfectly with an assortment of belt sanding machines and applications, offering a heavy-duty stripping and sanding tool for wood, aluminum, fiberglass, rubber, plastic and non-ferrous metals. ??? Total 20 PCS having Grits Indication on the cloth backing: 20 belt sander sandpapers consist of 3 PCS each of 60/80/120/150/240/400 Grits and 2 of 40 Grits, meeting all your requirements for different materials. Grits have been indicated on the backing to be clearly viewed. ??? Grit Selection Guide: 60 Grit sanding belt is fairly coarse - Heavy Sanding and Stripping; 80-150 Grit sandpaper is fairly medium - Removing Tiny Imperfections; 240-400 Grit Delivering a Super Fine Smooth Finish???