I've tried a lot of headphone sets. Plantronics are my favorite. It is a very good quality product. This was a exact replacement purchase for a headphone set witch I ruined by entangling the cord in a swinging door. The M175C seems to be the best corded unit available.

The headset is comfortable to wear but the sound quality is not great. It may be good enough for personal use but it's definitely not good enough for work. I bought it because I started working from home and I received regular complaints about the quality of the sound.

I am using this on a 12 line desk phone with a Bluetooth handset. I plugged it directly into the handset. It allows me the freedom to leave my desk yet to do all the functions of sitting at the phone. The sound quality is excellent. It is lightweight and comfortable. It does not flatten my hair.