Digital Voltmeter - Shows you the accurate and real-time voltage. After connecting the product to the battery, the voltmeter reading LED will appear. Safety Protection - Overheating, overcurrent, overload protection, automatically stops charging when fully charged; easy to use and install. WIDE COMPATIBILITY - Compatible with your mobile phone, tablet, GPS, digital camera, PDA and other USB accessories. : for Color: Black Material: Plastic+Metal Package Contents: 1 * Connector 1 * Link Line Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in a little different from the real thing. The measurement allowed error is +/- 1-3 cm.