I work at home and use my cell phone for many work calls. I've searched far and wide for headsets with top notch sound quality so I project a professional image. Most headsets have fine incoming call quality, so I've been mostly concerned with outgoing call quality (which many cell phone headsets are terrible at). Well, the MX505 is excellent for both. It's slightly cumbersome to get on, and a mirror helps get it on straight, but it is comfortable once on and the awesome call quality trumps any quibbles I may have with the design. It comes with two microphone booms - one longer than the other. I found the shorter one to work better. For me, I think the longer one was TOO close to my mouth, resulting in slightly overdriven/distorted outbound voice. With the shorter boom, my cell phone calls rival the clearest landlines. I have reached this conclusion after recording and reviewing several test messages on various voice mail systems. Thankyou Plantronics for being the one headset company that actually cares about engineering for sound quality.