In evaluations by The Hammacher Schlemmer Institute, this wireless all-weather speaker delivered The Best audio quality and signal range. Unlike a lesser speaker that was plagued by static, The Best Speaker's 100-watt digital amplifier, 6 1/2" downward-firing woofer and four 3" high-frequency drivers produced crisp, clear audio. In tests for signal range, the speaker maintained a connection with the included iPod dock transmitter 480' away when in line of sight outdoors. The Best Speaker's 41-channel transmitter operates over the 2.4GHz radio band, instantly jumping to open channels to avoid interference from microwaves and household appliances that jam other speakers' signals. The speaker's rechargeable NiMH battery provides up to 10 hours of cordless power on a three-hour charge or it can be plugged into AC. Buttons on the speaker let you pause/play and track forward/backward as well as adjust volume. It also accepts input from audio sources such as an MP3 player, computer, or CD player (3.5mm and RCA cables included). Its weather-resistant white ABS cabinet will endure years of outdoor exposure. Transmitter plugs into AC and recharges a docked iPod's battery. Speaker: 19" H x 10" diam. (31 lbs.)