Mr. Pen interlocking blocking mats come in a set of 9 mats, providing ample space for a variety of projects, including knitting, crochet, and other crafts. Each mat measures 12" x 12" with a 1" aligned grid, making it perfect for accurate measurements and consistent, precise work. Made from high-density, heat-resistant, and water-resistant material, these mats are designed to withstand frequent use while maintaining their durability and shape.