Item Type: Tappet Valve Adjustment Tool Material: Chrome vanadium steel Fitment: Fits for most motorcycles and ATVs with screw type tappet adjustments Package List 2 x Locknut Socket 1 x Driver The valve should be adjusted when the engine is cold. 1Function: The hand tool allows micro adjustment without disturbing the locknut which can be tightened when the correct clearance is achieved. 2Driver Design: The square type driver is designed with knurled handle, to ensure a secure grip, rough surface increases the pressure when grasping, making operation easier. 3Package Include: There are two 8 and 9mm locknut sockets, and one 3mm square type driver, which will make your repairing work more easily. 4Operation: You can use a 12mm wrench (not included) to hold the locknut socket while using square type driver to loosen or tighten the valve adjustment screw. 5Practical: Made of chrome vanadium steel, high strength, strong hardness, not easy to bend and break, fits for most motorcycles and ATVs with screw type tappet adjustments.