Perfect for headset, not so good for external microphone
On a smartphone, it can be used to adapt your 'old' headset or pedestrian kit to a 3.5 jack (TRRS format, plug with 3 black lines). This is not mentioned in the specification sheet.
On the other hand, still on a smartphone, when used for sound recording with an external microphone, the sound is nasal, and should be avoided for this use.
But the photos are accurate, and the delivery is top-notch!