SULLIVANS: Add-A-Mat Rotary Cutting Mat. The clever Add-A-Mat system allows you to easily expand your cutting surface by adding additional mats onto the edge. Notches in the corners allow all the mats in the system to be mixed and matched as needed! This package contains one 18×24 inch self-healing cutting mat. It is double-sided with 1-inch gridlines on both sides, 1/8 inch increments on the edge rulers, 45-degree angle lines, and markings identifying 1/4- 1/3- and 1/2-yard lengths. Additional mat sizes are available (each sold separately). Imported.