These Canson Montval Watercolor Blocks consist of 15 cold pressed, 140 lb sheets. Bound on all four sides, watercolor blocks prevent curling of the sheet thus eliminating the need to tape it down to another surface. When completed, your art can be easily removed from the block with a standard razor blade. Most blocks have an exposed area allowing you to locate the bottom of the sheet without harming the remaining sheets. Watercolor blocks are convenient for both field and studio use.