Mr. Pen interlocking blocking mats come in a 9-pack with 150 T-pins, providing a complete setup for shaping, aligning, and drying knitted or crocheted projects. Every blocking mat measures 12 x 12 inches and includes a printed grid to help align edges, maintain consistent dimensions, and position handmade pieces accurately. Each mat features a sturdy interlocking design with puzzle-style edges, allowing the pieces to connect securely and create a stable blocking surface.