Forged cast type rocker with original ratio of close to 1.3 with adjusting screw and 1/2" af nut.  profile of pad reduces side loading on valves to a minimum. Particularly effective on small bore engines although standard fitment on "S" type engines. Use recommended valve clearances. These are not original Cooper S rockers but the only alternative available and sold ready reamed for fitment--Some companies claim this to be to genuine specification but it clearly is not.