Rotary trimmer features a concealed rotary blade that glides smoothly up & down the trimmer for precise cuts. Versatile design allows you to switch out the blade type for different cut edges. Straight blade provides a standard straight edge. The wavy blade creates a scalloped edge for crafts. Perforated blade makes pre-cut marks for easy detachment. Each blade has a 12" cutting length & can cut up to 15 sheets at once. Plus, the square cutting mat can be rotated up to four times to maximize the number of accurate cuts before replacing.