Electronic Tachometer RPM Meter Hour Meter With LCD Magnetic Pickup Driven 100mm. Range: 0-4000 RPM Input : Magnetic Pickup Tachometer : Air Core based Voltage : 12V Operating voltage : 11-27V Size : 100 mm (Dia) Front ring : Black Case, Bolt and Clamp : Zinc Plated Dial(Base) : Black Dial (Printing) : White(when illuminated Amber) Indicator Pointer : White, Illuminated Deflection angle : 240° Connection Type : Stud 5mm Calibration : Dip Switch provided on back Connection : P= Positive terminal of the battery; S= Signal from Magnetic Pickup; N = Negative terminal of battery