The OLFA RM-12S rotating cutting mat helps you cut patchwork shapes without twisting fabric or repositioning your body during rotary work. It is a 12 in × 12 in (305 × 305 mm) self-healing mat with a stationary base and a top layer that rotates 360 degrees for repeated angle cuts. Rotate the mat instead of the project to keep alignment steady when making squares, triangles, diamonds, and other shapes.