O/B & 4 Stroke Gas Engines.(Mariner 30 & 40 HP 2 cylinder engines require a module (Mercury P/N 17461A2). Not tested for non-original equipment ignition systems. Not for diesels. Dial range: 0-7000 RPM. Fog resistant gauge comply with SAE J-1810. Black graphics on a white face with chrome ring and a black pointer with fire-orange tip. Scratch resistant curved glass lense with polished stainless steel, near-flush bezel. White perimeter and red thru-dial lighting. Sender code: O/B Alt or Coil.