Info about microphone in Apple Watch Serie 3

This is a very random question, but can anybody tell me specifically what kind of microphone was used in the Apple Watch Series 3? Was it a MEMS microphone? How can I find out what company supplied it? I know Knowles did some of Apple’s miniature mics. Lastly, I'm curious where I can find a simple explanation of how the miniature microphones in Apple Watches  work. What does the microphone consist of? In other words, how is it constructed? And how does it do the important job of recording audio in such a small form factor?