This is a USB OTG (On-the-Go) adapter that allows you to connect peripheral devices to a USB OTG-compatible device. On one end, there is a micro-B plug to be connected to a USB OTG device and on the other end is a female USB port that can be used to connect USB peripherals.

Many mobile phones, tablets and even boards such as Arduino Due and Odroid support USB OTG so you can connect a keyboard, mouse, flash drive or any USB devices.