The U100 features RCA line out as well as 3.5mm line in, so it can be used as Dedicated USB DAC or a stand alone headphone amplifier via the 3.5mm line input. The power supply of the U100, developed by ShenZhen YuLong Electronics Co.,Ltd, utilized an audio grade, special designed switching power supply with high-performance and very low ripple which assures the U100 has sufficient driving ability and excellent performance in a small size. The U100 has an elegant, compact housing (160*110*30mm) which is carefully made made aluminum alloy only weighing 0.48kg. All in, this is a full featured, well reviewed, DAC and headphone amp you’ll be glad to own.