Features:1, This product is fully functional, you can display the battery voltage, battery power, you can also connect directly to the phone or other charging equipment 5V.2, This product is suitable for all kinds of external power, mobile power, instrumentation and other equipment additional battery power voltage indicator and additional USB for phone charging and other functions.3, This product uses synchronous rectification scheme, low heat, energy saving and environmental protection.4. This product has a compact structure, making full use of space and reducing costs. Parameters1, static input current: 5-25mA, the lower the battery voltage, the lower the current.2, USB output: 5V/2A (USB setting for Apple recognition, android recognition setting)3, the efficiency of the USB buck is up to 96% (due to the synchronous rectification circuit, the buck conversion efficiency is high and the heat is low.4, 8 segments power supply resolution: 10% 25% 40% 50% 60% 75% 90% 100%5, the accuracy of the voltmeter is about 2%6, the operating temperature: -10 - +65C7, the operating humidity: 10 - 80% (non-condensing)8, the hole size: 45 26 18mmPackage Included:1 X Digital Voltmeter Battery Panel Meter With USB Output