Jensen JS800 100-watts RMS deep-bass Subwoofer. The JS800 features an 8-inch heavy-duty acoustic suspension speaker encased in a cube cabinet measuring 13 x 11.8 x 15.6 inches. Subwoofer has its own built-in amplifier, so works with any sound system, and a POWER switch that turns off/on the AC supply or sets the Subwoofer to STANDBY mode. LINE-IN JACK and L,R Speaker-IN and OUT terminals provide two connection options for augmenting stereo or home theatre. LEVEL CONTROL balances the loudness of the Subwoofer relative to the front speakers.