Sounds ok, fits into my ears much more comfortably than the outsized Blackberry standard earphones. The "on/off" button on the mic isn't mute (mic on/off) as the label might suggest, it's actually "end call". Watch out for that!
Excellent ear pieces that are great for tele-conference calls, though not great for music. One thing to watch is "shouting". They reduce environmental noise and for some reason I end up shouting. Not good in an open plan office but so comfy, I don't really care!