Lightning Adapter Headphone Jack Audio for iPhone7/7Plus iPhoneX/8/8Plus Headphone Adaptor Lightning Cable Earphone Adaptor Support Charge Volume Control Call Compatiblefor iOS 10.3 or Later

This multi-meter plugs directly into any USB socket and allows you to connect any USB cable into it for charging or data transfer. It displays on screen the voltage and current which is being output, acting as both a volt and amp meter. It is powered inline so no battery is needed, and uses low resistance components with <4mA power consumption for the most accurate readout. A 3 inch extension flexible cable means you can turn the LCD screen to face you - it won't be fixed facing the floor/wall regardless of how the USB socket is oriented. It uses a large LCD display is easily visible both indoors and in bright sunlight, and uses a switch to let you choose between displaying current and voltage. The meter is useful for solar panels with USB outputs, since it will then allow you to position the panel to maximize the energy it outputs, see what factors affect the panel's performance, and also to see when the output is too low to be worth using the solar panel. It is also allows you to compare the power of different USB sockets and study the quirks of USB charging. It has an upper limit of 3A.