Battery-powered mode / Normal Blu-ray burning:
*Requires only (1) USB connection to Mac or PC desktops and notebooks.
*No additional power supply or wall adapter required for use
*Product stays within USB spec (draws <500mA from system)
Dual-USB mode / Heavy Blu-ray burning :
*Connect to your computer system via (2) USB ports (for increased power)
*Required for Blu-ray disc burning longer than 3 hours (ex. full 50 GB Bluray disc write)
*Exceeds USB spec (draws 1.5A from system)