This is a service piston stopper that requires holding the crankshaft in place Can be used for clutch service or flywheel nut removal or maintenance of weed killers and leaf blowers Just remove the spark plug and screw this tool into place and wedge it lightly The end is fully machined to prevent damage to the top of the piston Very easy to use and very convenient to have around if you are doing your own saw or other 2 cycle work Product description Features: This is a service piston stopper that requires holding the crankshaft in place. Can be used for clutch service or flywheel nut removal or maintenance of weed killers and leaf blowers. Just remove the spark plug and screw this tool into place and wedge it lightly. The end is fully machined to prevent damage to the top of the piston. Very easy to use and very handy to have around if you are doing your own saw or other 2 cycle work. Specification: Condition: 100% brand new Color: Orange + Black Package Weight: Approx. 308g Package included: 1 set of xClutch removal tools Note: 1. We provide clear pictures, measurements where possible. Please check as much as possible to make sure the item is the one you need. 2. Please allow 0.5-1 inch difference due to manual measurement. (1 inch = 2.54 cm) 3. There are no instructions included in this kit. Professional installation is highly recommended! 4. Rotate the motor clockwise or counterclockwise until you feel the piston is against the tool and you are ready to do your service. . Remember that most chainsaws have a left-hand thread on the clutch side.