Palm-sized headphone amplifier with stylish design that delivers a genuine vacuum tube Hi-Fi sound with high clarity, ideal for vocals and classical music. It also provides a Bass Boost feature for amplified sound of the low end. It provides a headphone impedance of 16-300 Ohm, total output power of 140 mW x 2 or 280 mW (16Ohm load) or 12 mW x 2 or 24 mW (300Ohm load), and frequency response of 10 Hz-65 kHz. The body of the amplifier is made of sturdy alloy and features a micro USB connector that provides powering for the built-in 1800mAh lithium-ion polymer battery with lifespan of 16-18 hours. A USB cable (for battery charge only) and audio cable are both included. Total harmonic: <0.1%. Signal-to-noise ratio: ≥85dB. Dimensions: 120 x 78 x 13.6 mm. Weight: 135 g. Black colour.