I have an 850 and was pretty happy with it. It works fine on the 737. However despite coming with a nice protective case, which I always used, after a couple of years, naturally out of guarantee, the plastic connection on one of the earpieces broke in a way not easy to fix. My fault I guess but suggests they are not terribly robust. Also the fact that I have not bothered getting it fixed and have been using the company issue non anr headset for over a year tells me I cannot be missing it that much.