What means “1000 physical units” in the standard-license?

If you like to license music from the Proud Music Library e.g. for a corporate video, which is used for trade fairs or the company’s website and offered to be downloaded, the standard-license will cover this kind of use. Regardless of how often the video is downloaded or replayed. The limitation of 1000 units is just refering to physical units such as DVDs, CDs or memory sticks.