Ideal for outboards and stern drives! With stainless steel bezels, brushed aluminum dials and black pointers, Sterling instruments give a bright, gleaming look to any dash. Perimeter lighting provided for night operation.Features: Brushed aluminum dial, black graduations/numerals, black pointer.; Scratch resistant curved glass lenses, with polished stainless steel, near flush bezels.; Perimeter lighting.; U.S. and metric scales, with ISO symbols, where appropriate.; Optional add-on square bezels for modular appearance.; Additional Details: Dial Range: 0-7000 RPM; Size: 3"; Tachometers (Electric): O/B & 4-Stroke Gas Engines; Sender Code: O/B ALT./COIL; Note: Mariner 30 & 40 HP (2-cylinder) engines require a module (Mercury P/N 17461A2); voltage: 12 VDC; Current Draw: 0.10 - 0.15 A; Operating Temperature: -40C to +70C; Ingress Protection: IP 65; Bezel O.D.: 3.74; Housing O.D.: 3.39; Hole Size: 3.43;