I bought two of these (on clearance), thinking they would be great, without the ADC.
After taking them apart, I saw they are regular 5mm (?) electret capsules, not the lauded KE4 capsule in MKE2 and other classic mics.
Still would be great for old iPhones. Provide record and playback in a nice "sporty" package. Certainly an improvement on standard Apple earbubs with the inline microphone.
Have fun!