Ultra high-quality portable amplifier, housed in a polished metal chassis. Delivers clean, well-layered sound thanks to precisely assembled internal electronics, powered by a long-life rechargeable 4.2V Lithium Ion battery that will amplify your music listening experience for 60+ hours from each 3 hour charging cycle. Compact to fit easily into any pocket or tankbag for take-anywhere audio portability. Simple operation with On/Off toggle switch, 3.5mm headphone output jack, AUX input port, and rotating volume knob. Output power 150mW (32 Ohms), signal/noise ratio 101dB, frequency range 17HZ-100KHZ, headphone impedance range 8-32 Ohms. Assorted colors. 3.6"×2"×.43".