Like all the Studio 180 Design rulers and processes, the Four Patch Trimmer tool and technique will have you build your units slightly oversized and then quickly trim them to perfect shapes. The Four Patch Square Up© Tool is designed to work with units that finish to whole or half inch increments, from ½” finished up to 6” finished unit sizes. The tool’s perfectly engineered lines are designed to quickly locate and align with the unit center and the sewn seams, allowing for easy trimming on all four sides. The accuracy is amazing!