The BlueAnt Interphone works as advertised with good volume and clarity. It's weakness is it's short battery life. We have used them on several rides and marvel at the way they function as a Bluetooth with the Zumo and phone, but it is the bike to bike communication that is really great. It says in the advertising that they reach 490 feet, however we have had up to a half mile separation and still had communication. You can carry on a conversation as if you were sitting next to someone on the sofa. After about 4 hours, you're out of battery and all is lost. You'd think that in today's era of 8 to 10 hour rides that an otherwise excellent device such as this would be able to last the ride. There's no way to charge the battery on the go or replace the battery with a spare. You have to put the unit on the 115v charger to get it to work again. I really can't reccomend this product unless you intend to use it only for short trips.