Excellent sound, clever design. Hear, hear!!
Plantronics MX505 Headset for Cordless or Mobile Phones with 2.5mm Connection
Now that New Jersey drivers MUST use a hands-free cellphone device OR an earpiece like this, I searched hard and tried several. This is the best of the crop, super clear sound even with wind noise around the vehicle. It's easy to wear, fitting under the ear (vs over it) and the earpiece swivels for true-fit comfort in right or left ear. My callers tell me the mic delivers very clear sound as well. I am v. happy with this purchase and Amazon made buying it easy -- as always.

My wife can hear me...
I purchased this one because of the wind/noise cancellation microphone. My wife can barely hear the background noise of my car when I am driving. Now I can hear her yelling more clearly and she can hear me say "Yes dear" with no issues. Honestly, I am glad I did my research and picked this one up.

Excellent corded headset
I will keep this short.

I love this. Great sound in and out. Mute. Variable volume control that works very well. The comfort is good. The design is unusual but it works for left or right. adjustable mic position. Good wind blocking. Never any complaints from the receiving party.

I have had 2 of these. I ruined the first. In the end I liked it better than all the other corded headsets and went back.

I would recommend this. I am very happy with it.

surprisingly great wind reduction
This headset has wind reduction that works GREAT. I can drive on the freeway with the windows down and trucks going by, and the person I'm talking to can still hear me clearly.

The reduction works best on wind, or noises that sound like wind (kinda white noise). So it doesn't reduce noise as well from, e.g. nearby radio music or loudspeaker announcements in the mall.

The headset has a mute button, works well, convenient. The mute function is a mechanical switch (not an electrical button). The indicator that lets you know if it is muted or not is a red/green tab - it doesn't light up, hard to see in the dark.

Also, the Amazon overview says that this headset has a call answer/end button - it does NOT. If you really need it, try the MX510-X1 Plantronics MX510-X1 Mobile Headset for most phones with standard 2.5mm headset jack - Audiovox, Bla - it is a similar headset that DOES have a call answer/end function.

Plantronics the best but this model not that Good
Plantronics is known for making the best headsets but this model does not live up to that standard. The design is great but the clarity of voice (mic.) is low grade and the volume of voice sounds to your listener like you're talking into the mic. from another room.

The purpose of this feature is to reduce background noise but I find it to not be usable for regular conversation is a quiet environment.