3.5mm Headphone Mic Splitter/Audio Adapter.
It allows you to connect a gaming headset with separate headphone and microphone plugs (3.5mm TRS) to a device with a single combined 3.5mm TRRS jack, like a newer laptop, smartphone, or gaming console controller.
The black male plug connects to the device, while the red female jack is for the microphone input and the green female jack is for the headphone output.
This adapter is not designed to split audio output to two sets of headphones or speakers.