The ground-breaking patented ratchet mechanism of the rotary circle cutter easily and efficiently cuts clean, perfect circles from 1-7/8" to 8-1/2" every time. Great for making circles for Yo-Yo's, Cathedral Windows, Drunkard's Path, etc. Designed for both right and left-handed use. Includes a built-in blade cover for safety, and a plastic guard to cover the pivot spike when not in use. Uses RB18 (standard) replacement blades.