[Dual Outputs] :The M15i, equipped with four CMA engines, supports 3.5mm single-ended and 4.4mm fully balanced output. [Patented AMP design] : patented Current Mode Amplifier “CMA” technology (Global PCT Patent Number: US 9,614,483 B2), enables the small device unbeatable performance: low power consumption and heat generation; large bandwidth up to 1MHz, ultra low distortion to 0.0003% and wide range impedance adaptive 8ohm ~ 600ohm, it works with most of the headphones in the market perfectly.