Corporation RWC has introduced a vacuum tube amplifier set RM-VA1S for the iPod though you can also connect other players. The device has vacuum tube type 6N1 2, 6E2 1 loading and the amplifier output is 15W×2channels with signal-noise ratio above 86dB. The external size of amplifier section is 260×145×130mm (width × depth × height). The size of the tweeter is 1 inch and the woofer is 4 inches wide of the two-way bookshelf speakers with output impedance of 4Ω. Available in Japan from January 25th 2007 for 69,800 Yen ($ 590).