The Boostaroo portable audio amplifier is a terrific solution for riders that use a portable audio source (such as an MP3 player or portable CD player) with earbud speakers under your helmet. The Boostaroo approximately doubles the volume level that you get from the device normally, and also provides three outputs so that you can share the sound with a passenger. The compact unit runs for hours on two AA batteries.

The Boostaroo can be used with XM radio on some bikes, especially those that have a fairly quiet fairing. On a noisy bike, you'll be better off with the Mix-It amplifier.