RERERPTG 2 in 1 Tachometer Gauge Digital RPM Voltmeter for Auto Motor Rotating Speed: Car Electronics. we adopt 0.36in digital tube, suitable for 1~8 cylinder autos and motors 12V diesel engine. 。 Our products are with shells and shine brighter. 。 Display battery voltage before and afrer engine start 。 When 12V car battery over voltage (overvoltage) or undervoltage, it will be flashing alarm. 。 When battery voltage is less than 11V (< 11V ), or hgiher than 15V ( 。 100% brand new and high quality。 Features:。 we adopt 0.36in digital tube, suitable for 1~8 cylinder autos and motors 12V diesel engine.。 Our products are with shells and shine brighter.。 Display battery voltage before and afrer engine start。 When 12V car battery over voltage (overvoltage) or undervoltage, it will be flashing alarm. 。 When battery voltage is less than 11V (15V), it will flickering alarm and display the real battery voltage.。 Specification:。 Working Voaltage: 8v~17v。 Working Current: 40mA。 Voltage Accuracy: ±0.1V;。 Rotating Accuracy: ±round/min。 Maximym Rotating Gauge: 100-31800round/min。 Bulb Color: Red。 Quantity: 1 Pc。 。 。 。