I had two NW10s because the mics only last 10 hours vs. 20 on the necklace, and the necklaces did not pair well with the other mic. One mic started only lasting 4 to 5 hours. Bought a 3rd NW10.
One side of the other NW10 got plugged. Ordered a 4th NW10 because of the mic pairing problem.
The newer NW10s kept having mic cut-out problems, even just lying watching TV.
The NW20 works MUCH better with the mic and does mic pairing with an older NW10 mic. However, now having troubles with controls on NW20 not working after charging.