Tappet Adjuster Tool Set Integrated repositionable wrench handle holds the lock nut while the drivers are used to loosen or tighten the valve adjustment screw, 8 mm, 9 mm, and 10 mm lock nut sockets; and 3 mm square, 4 mm square, and straight slot type drivers included, Allows precise valve lash adjustment without disturbing the setting when the lock nut is fastened, Fits most motorcycles and AT with screw-type tappet adjustments, Knurled knob on adjuster drivers ensure a precise and secure grip