Koso DL Universal Electronic Tachometer Stainless Stainless steel body with easy-to-read digital display with blue backlight Digital display shows tachometer with 0-18,000 rpm range (100 rpm resolution) and water temperature Adjusts to all engine types When off, face turns completely black Works with single- or dual-fire ignitions 55mm (2.15in.) Dia.; 61mm (2.4in.) Dia. w/ bezel