Genius SP-U120 Black Stereo Speakers Active black stereo speakers with volume control and earphone jack. Power is supplied through a USB port from a PC or notebook. You can use it just about anywhere. Key Features: Total RS 1 W output power 3 watt RMS driver unit: 50×90 mm frequency response: 160 Hz ~ 20 KHz signal-to-noise ratio: 80dB crosstalk: 40dB volume control power supply: USB audio in: 3.5mm plug audio out jack audio cable: 1.2 m USB cable: 1.45 m dimensions: 66x174x78 mm size of giftbox: 190x75x185 mm speaker body weight: 470 g power supplied by USB port from PC/notebook volume control 3.5 mm audio stereo jack.