Zen Stone or new Stone Plus. Priced at just ¥3,980 (about $32), the TravelSound Zen Stone speaker is primed for all the itty-bitty, 0.2W x 2-channel thimble thumpin' action you can handle. Better yet, it'll annoy the audiophile in your family for up to 21-hours off battery. Available Amos 'n Andy or Martin 'n Lewis. Think about it.