Zalman 2-Channel Multimedia Vibration Speaker, Piano Black (ZM-S100) Total RMS Power: 2Wx2 / Frequency response: 90Hz-20KHz / Driver Unit 2" full ranger speaker / Power Source: USB & DC5V / Dimensions: 70(W)x75(H)x 72D)mm USB directly charge no adapter needed. Vibration, slide proof pad applied. Compact and convenient with a built in volume control. Looks great any where you put it, with 70(W) X 75(H) X 72(D) compact cube design. Luxurious design with high gloss piano black in collaboration with Zalman blue. Compatible with smart devices such as smart phones, smart pads, and MP3 players. Low pitch reinforcement enclosure structure, with driver unit stored that clearly tones both middle pitch and high pitch. Enables PC and smart devices withoutstanding Audio performance. Channel: 2.0 Frequency Response: 90Hz - 20KHz Output: RCA Audio, Input: 3.5mm Audio Power Source: USB / DC 5V Compatibility: Windows 7/ XP/ Vista/ 2000 Vibration, slide proof pad