The block is well made and the clips for holding the sandpaper are easier to use than other types of sandpaper and apparently hold sandpaper firmly enough. The main problem is that the flat grinding surface of the block is only 2 5/8 inches by 7 3/4 inches. The size of a 1/3 sheet of sandpaper is 3 5/8 inches by 9 inches. The block is too narrow for the sandpaper, and 1 1/4 inches total for both ends of the sandpaper to attach the paper to the block is very tight. Maybe those who rated the block 5 stars wouldn't mind. 1/2" sandpaper on each side is useless, or they cut off 3/4" sandpaper before attaching to the block