I was hoping these speakers would provide a viable alternative to wearing earbuds under my helmet on the bike, however, a cheap pair of earbuds works much better. My Icon Alliance SSR helmet has two pockets for speakers, and these slipped right in-size was ok. However, when I hooked my ipod up to these to try out, I got the tinniest, scratchiest sounding music I've ever heard. Zero bass, waaaaay too much treble, and you get static whenever the headphone jack even slightly moves(other headphones on the same player don't, so it's not the ipod's fault). Trying them out on the road I had to have the ipod's volume at max, and then all I heard was tinny schreeching. Lowering the volume slightly improves quality, but then you can barely/not at all hear it-and my bike isn't that loud.
These may be ok for a voice comms system or a way to use walkie-talkie type radios on the road, but for music, they absolutely suck. A $8 set of "clip on" earbuds have much better sound quality and better volume.