I have used a Jabra earset on my nokia 5100 for years and love it. By far the best headset I've tried. So I expected similar quality when I bought the earboom for my home phone (with a 2.5mm jack). The sound quality is excellent and the ear gels work great, but people can't hear unless I yell. I've tried taking off the foam, twisting the mic closer to/further from my mouth, up and down and no luck. This is especially disappointing because I am indoors in a quiet room and people can't hear. If I had thought to keep the packaging it would be on its way back right now. But my Jabra earset for my 5100 (with built in adapter) works great.