I purchased these for my Jawbone II. It's a great headset, but the sound quality isn't too good (phenomenal for the person I'm talking to, but not for me). The included kit doesn't make a good seal in my ear, and it's not loud enough on most calls.These ear gels fit on the Jawbone II. They're a little small, so it's not a perfect fit, but I haven't had one fall off yet.The fit in my ear is another story. When I first used them the Jawbone kept falling out and putting on one of the bands pulls the set at an angle that pulls the tip of the ear gel out of my ear. I was ready to cut my losses when I decided to try my other ear ... fits perfectly. Since the ear gels aren't really that soft or pliable, I think it really depends on the shape of your ear. In my case, I'm quite happy using them on my Jawbone, but your mileage my vary.