Smaller than the length of a match but so powerful you cannot look into them, these use six High Intensity LEDS, supplied complete with M6 nut for secure fixing small enough to hide behind a grill but bright enough to show up, these are Emarked so compliant to exacting European standards . Sold as a pair so if you want 4 you must order two pairs, they are in a Black or chrome finish. The website price includes Ballast resistors so they will flash at the correct rate.
http://www.digital-speedos.co.uk/min...black-20-p.asp
http://www.digital-speedos.co.uk/min...rome-431-p.asp