Groovers add extra traction in minutes. Tapered, razor sharp blade grooves fast and easy. To operate, insert a blade into groover, set blade height with a tire depth gauge and set the power level. Features triggerless activation Ð simply place the cutting edge against the tire surface and press down for instant heat. Includes 2 each 4/32", 6/32", 8/32" and 10/32" flat blades.