Coral 4" Tachometer (7000 RPM) (All Outboard) Perimeter-lighted Black dial with stylish White and Blue graphics, Black aluminum bezel with burnished leading edge, contoured White pointer, and flat glass lens.Electronic tachometers work by counting pulses generated by the ignition system, alternator, tachometer signal generator or magnetic pickup sender. The tachometer is hooked up to +12 VDC, Ground and one of the signal sources.4"- Hole Size: 3.375" (85mm)Specifications: Scratch Resistant Lens; Black Aluminum Bezel; Contoured White Pointer; Factory P/N TC9036*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. - cis2:mm5mnJlm -Specifications: Gauge Type: Tachometer; Gauge Size: 4"; Box Set: No; Voltage - Input Range (Volts): 12/24 V; Series: Coral; Box Dimensions: 6"H x 6"W x 7"L WT: 0.7 lbs; UPC: 759266330054;