The Hula hoop allows the technician to comfortably keep his hand and eyes where they need to be while repairing the dent. Designed by Martin Sadler, this 18 1/2 “ circle and 1/2” diameter Interchangeable Tip heat-treated stainless steel tool will help speed up your work! PDR industry standard 5/16-8 threading. (Tip not included.) Bonus: Check out this video to see this highly accessible tool!