The iDefender3.0® protects against the common problems of ground loop noise and noisy USB power: 1. Breaks noisy ground-loops. Significantly reduces system noise floor and makes for better dynamic contrast, warmth and resolution 2. Disconnects the USB Power from the PC and replaces it with a clean external power (optional iPower* 5V for ultra low noise) 3. USB3.0 port technology – most advanced and highest USB specification To be used directly at the Source such as the PC usb port, it breaks ground loops and cuts the noisy USB power line. From computer audiophiles, musicians, home studio artists to pro audio customers, it improves audio playback quality at home and on-the-go. For DACs that require USB power, to obtain the best sonic performance, the iPower 5V is recommended to supply the iDefender3.0®.