Chesapeake Black 5" Tachometer w/Digital Hourmeter - 6000 RPM (Gas) (Inboard)Perimeter-lighted black dial with stylish blue and white graphics, polished stainless steel bezel, contoured White pointer, and domed glass lens.Electronic tachometers work by counting pulses generated by the ignition 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.5" - Hole size: 4.375" (112mm)Specifications: Anti-scratch glass lens; Perimeter lighted back light; 12 VDC negative ground; Can be adapted for 24 VDC systems; Scale - 0 to 10000 Hours; Factory P/N TCH323*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: Voltage - Input Range (Volts): 12/24 V; Gauge Size: 5"; Gauge Type: Tachometer w/Hourmeter; Box Set: No; Series: Chesapeake Black; Box Dimensions: 8"H x 8"W x 8"L WT: 1.35 lbs; UPC: 759266337633;