TOOGOO(R)Thermometer Voltmeter Voltage Detector Battery voltage measurement Temperature exterior and interior alarm clock LCD digital display for car Voltage Detection car battery voltage; Cable cigarette lighter: approx. 2.2m; Supply Voltage: 12V; Detector Dimensions: 9.5 * 6 * 6CM 2 light background colors optioned; LCD content can only be displayed when connected to the car power supply. If you use only batteries, LCD can only display time information, and in this case the blue light in the background and other operations is not displayed, that is to say, if the Article is powered by battery, it detected nor temperature or voltage battery Detection of indoor and outdoor temperature (with the supplied sensor); Switch display temperature in  C or  F 1x manual in English; Alarm function; Display Time or Date, but the time and date can not be displayed at the same time This fantastic multi-functional display plugs directly into the electrical system of your car and offers you a wealth of accurate and useful information in an easy to read compact device. You can also define alarms to tell you it is cold on the outside