Easy to use like a compass, this tool cuts circles of diameter between 12mm-300mm. Simply move the guide to the measurement you wish to cut (noting that markers resemble diameter not radial width) and push the plastic lock into place to secure position. For dimensions between 150-300mm, first move the needle to measure you wish, then slide out the black panel all the way before securing the lock in place. Only cuts in one direction. Will put pin hole in middle of circle unless using the included paper protector. Suitable for cutting paper, lightweight cardstock, acetate and photographs. Includes five replacement blades and three leads for drawing circles.