Euro Black 4″ Tachometer w/Systemcheck 7000 RPM (Gas) f/ Johnson / Evinrude Outboard)Perimeter-lighted Black dial with bold White graphics, Black aluminum bezel, contoured White pointer and flat glass lens.Electronic tachometers work by counting pulses generated by the ingition system, alternator, tach signal generator or magnetic pickup sender. The tach is hooked up to +12VDC, Ground and one of the signal sources listed above.By selecting the right tach and setting the switch on the back to the correct position you let the tachometer know how many pulses are sent per each engine revolution.These tachometers have a warning light system built into the dial that show off warning indicators when a fault is detected from the engine.4″ – Hole size: 3.375″ (85mm)For Engine Types:Johnson and Envinrude OutboardSystemCheck Warnings:No OilEngine OverheatCheck EngineLow OilSpecifications:Anti-scratch glass lensPlastic Cases for corrosion resistance and long lifePerimeter-lighted Black dialCan be adapted for 24 VDC systemsFactory P/N TC9951*Sold as an Individual**Gauge Cover not IncludedThis product may not be returned to the original point of purchase. Please contact the manufacturer directly with any issues or concerns. Specifications:Gauge Type: Tachometer w/System CheckSeries: Euro BlackVoltage – Input Range (Volts): 12/24 VGauge Size: 4″Box Set: NoBox Dimensions: 5″H x 6″W x 6″L WT: 0.7 lbsUPC: 759266328501Quick Guide (pdf)