What is the smallest headphone/earphone connector you know of?

I am looking for the slimmest connector in the headphone/earphone space.

Hell, if you think you know of a very slim (and durable/reliable) connector that can be implemented into a headphone, let me know.

So far, the ones I can think of are 2-pin connectors and the Estron T2. However, the slimmest one I know of is USB-C. Wondering whether anything as slim as USB-C exists…

Quick edit: If not, do you know any connector manufacturer in Europe that has something like that?