LIHAN 2 USB Car Charger,12V/24V Voltage Meter, Output 4.8A, Cigarette Lighter Plug Adapter Compatible with iPhone,iPad, Samsung, USB Charging Devices, Silver;

Dual USB Car Charger,LED Display for Vehicle Voltage
Dual USB ports allow you to charge two devices at once. With both 2.4A ports, you can conveniently charge Smartphones , Tablets and other devices. Smart charging technology identifies your device to deliver optimum charging efficiency and protect against overcharging.
See If Your Car Has an Electrical System Voltage Problem
Voltage too low:Car won't catch fire,intermittent dead fire, insufficient lighting lights etc.
Voltage too high: Causes abnormal signal of the shift solenoid valve, engine instability, speaker doesn't ring and other issues.
Car battery voltage monitoring feature allows you always know the battery state of health, prolong car battery life.

How to use it :

1.Plus this car charging into car cigarette lighter hole, it will detects the car battery voltage automatically and shows on the screen.
For 12V car, voltage display of car battery under 11.5V or higher then 14.9V means a car battery issue.
For 24V car, voltage display of car battery under 23.1V or higher then 27.3V means a car battery issue.
High or Low voltage can indicate a battery issue.

2.Connect your device to the car USB port charger by suitable cable.

3.The input current will decrease until your devices battery is full.
A subtle LED glow from the USB ports allows you to easily see where to plug in devices in low light.

Compatible for Apple iphone 4/4s,5/5s/5c,6/6 plus,6s/6s plus,7/7plus,x,xs,max,ipod,ipad,Samsung / LG / HTC. Most of phone and tablet

Package:
1 x Dual USB Car Charger.(Charging Cable NOT included)