Combined dual USB interfaces and LED digital display voltmeter into a combo. With built-in intelligent voltage monitor, this 2-in-1 voltmeter is able to show you an accurate voltage value at anytime while you're driving, helping you to easily notice the battery running condition. Features - Color: Blue. - Material: ABS. - Size: 4x4x5cm. - Built in intelligent voltage monitor, with LED digital display, it real time shows you the accurate voltage status of car or motorcycle, more secure for driving. - Dual USB interface design with single output of 2.1A (max total output of 4.2A), it quickly charges for most smartphones, tablets, GPS, digital camera, PSP/MP3/MP4 and other USB-devices. - Apply to all USB charging mobile phones or other electronic products. Run multiple accessories at one time, very convenient and easy to use. - It is specially designed to steadily work at the operating range of 12-24 volt. - Multifunctional product with blue LED indicator light, perfect for travel use.