5 to 11 US. detail. This would be a great product except instead of using an electrical conductor that is resistant to corrosion (gold plating maybe?) they apparently chose something that does not do well with chlorine. The bamboo materials are very high quality. I own Apple Airpods and Airpod Pros, as well as audiophile-quality high-end open headphones and multiple DACs. The only actual negative feedback that I would have for this is likely on my end: if I listen closely with the headphones plugged into the mic, I hear a little bit of fuzz. The sound came out even and extremely clear, every range was crisp and clean. For whatever reason, Merrells always fit me best - Im right between a 9 and 9. I?m a nurse who works 13hr shifts on a busy ward. When she got it and tried it ?it ?s perfect fit.