Koso GP Style Universal Tachometer W/Water Temp Gauge Easy-to-read white or black background with blue backlight Stepper motor keeps dial needle stable through the heaviest vibrations Gauge dial shows tachometer with 0-9000 rpm range; adjustable by units of 100 rpm Blue back-lit digital display shows water temperature Gauge measures 55mm (2.17in.) Dia. without bezel; 61mm (2.4in.) Dia. with bezel