SP-U115, whose power is supplied through a USB port from a desktop and notebook. They use 50mm speaker drivers for loud and clear sound performance. Total RMS output 1.5 watts. Total peak power 3 watts. Works with any computer system using a standard 3.5mm audio plug. There's a convenient knob on the side to adjust the volume. Insert the USB plug into a PC or notebook for power and the 3.5mm audio plug into a music playback device, such as a PC, notebook, MP3 or CD player and enjoy your tunes.