SallyBest&reg; Multifunctional 4 in 1 Universal Auto 12V / 24V LED Backlight Display Digital Car Thermometer / Car Battery Voltmeter / Noctilucous Clock / Freeze Alert Feature: Multifunction, Thermometer/Voltmeter/Noctilucous Clock/Freeze Aler 4in1. It shows synchronously the temperature of inside and outside the car, car battery voltage and time It can measure the temperature of the car from - 10 to 50 celsius degree. Voltage Measuring range: 8 - 30V. Power of Rate: 0.6W. Work Temperature: - 10 ~ 60 celsius degree, suitable for advertising promotion, festival, awards cer