I'm using UGREEN Headset Y-Splitter Adapter (3.5mm TRRS (CTIA) male plug to 2 x 3.5mm TRS female jacks for external microphone and external earphones) for my McBook Air Notebook, to connect to an external microphone and external earphones. As seen from the photo, the UGREEN Headset Y-Splitter Adapter (the 3.5mm TRRS 4-poles male plug) is plugged directly to the Headset input jack (3.5mm TRRS 4-poles female jack) of the McBook Air Notebook and the external microphone and external earphones are plugged into the Y-Splitter Adapter's two other 3.5mm TRS female jacks according to the marking on the cables. The other 2 photos show the computer screen confirms from the Sound Preference that the computer recognises the External Microphone as the sound input source, and the External Earphones as the sound output source. This works perfect for online conference on Zoom and Meet conference call. Highly recommend this Y-Splitter Adapter for all MacBook Notebook computer.