My company has a lot of these and they work well, but the latest set I ordered don't work well with my Polycom IP550 phones, and even with the right cord (that's important too.)

This was supposed to be a special purchase, an upgrade from my work set, but other than the fact the cord is not twisted it actually seems to be less comfortable and the sound quality is not as good as the old set which was the same brand ( just the older version).

I tried two different adapter cords (at an extra cost of $33), tried working with Plantronics (they sent me a new set in case mine was defective) and the problem wasn't resolved

The binaural set is much better than then the Jabra one piece I have been using in the past

The set is comfortable however the foam ear pads become a little warm after wearing the headset for a while.

Got a great set for 20.00$ at Walmart