This is a solidly designed product. It has a 60, 100, 180, 240 and 320 abrasive side. the 60 and 100 are on one block and the others are on both sides of the sponge. I bought them because they were advertised as a sanding and finishing foam blocks. As you can see from the grits there are not any real finishing grits. They do knock down seams really fast on chassis and other large surfaces, but that is all I really use them for. Be clear it is a good product. I just don't have a great use for it. I wish they had Higher grit blocks. They would be great for wet sanding car bodies before paint and in between base and clear coats.