Polishing cloth strips are coated in an insoluble aqueous mixture of cotton and rayon mineral particles called a slurry. This strong and durable backing gives the strips a consistent and uniform finish, which distinguishes them from traditional polishing papers. Contains 18 strips: 2 sheets per grain: 360/400/600/800/1000/1200/1500/2000/4000. The smaller the grain, the coarser the grain finish, the higher the grain means a finer grain finish. Colors can include gray, blue, white and more.