MICTUNING Dual USB Chargers 4.2A with Blue LED Digital Display Voltmeter for iPhone iPad Input voltage: DC 12V/24V; output: DC 5V 4.2A. MICTUNING new designed in 2016, combined dual usb power socket with blue led light voltmeter, fit in your car switch panel, great for charging and voltage checking Works great with smart technology, over-heated, over-current, over-charging protection. Charging will be automatically stop when battery is full, your guarantee of safety Compact design and practical function, high quality environmental ABS material, can run multiple accessories at one time, convenient and easy to use and install Compatible with: popular devices USB 2.0 charging mobile phones or other electronic products, such as vehicle,GPS, mobile phone, camera, mp3 Mounting size (LxW): 1.47"x 0.84", fit most of the cars