Gunson G4094 - Clik-adjust Tappet Adjuster with micrometer accuracy ensures valves (both inlet and exhaust) open and close correctly resulting in better engine performance. Valve clearance is easy to adjust on all push rod engines or OHC engines with top adjustment using a screwdriver slot and locknut. Tappet adjustment is an essential servicing job but it is always a fiddle. Until evolution gives us an extra hand to hold all the required tools, there\'s Clikadjust! CLIKADJUST is an ingenious method of tappet adjustment that uses a distinct click to represent one thousandth of an inch of clearance. Start by closing the gap right up, and then count the required clicks until you reach the required setting. Quicker and more accurate than the conventional method, and so saves time, petrol and power. Suitable for conventional tappets and pre 1968 Fords.