They work great, been using them for 4yrs, the only problem I've encountered is ear wax build up, but they have a little flip-up cap that can be removed to clean them, replace the batteries once or twice a year with standard hearing aid batteries that come in a 10 pack. When I wear a face mask, sometimes it causes some feedback, but adjusting the volume solves that issue. I wouldn't want to wear them full time, but for 6-8hrs a day they work Ok.
Tim