Use these joiners to connect two or more of any size UltiMAT Cutting Mats together to create endless size options. This 9 piece assortment includes 4 Corner, 4 Twin and 1 Cross (Centre) piece. 3 ply, 3mm thick and extra durable. Includes 4 Corner, 4 Twin and 1 Cross joiners. For use with the 12″ x 18″ (#3906018), 18″ x 24″ (#3906024) and/or 24″ x 36″ (#3906036) UltiMATs.