The Rolls PS16 supplies the DC power and distributes the Monitor signal to up to ten of the PM50s, the PM50sOB, and the PM350 units by connecting them with ordinary stereo phone cords. Although the PS16 has only 4 output jacks they can be multiplied with "Y" adapters for many more outputs. This makes a much "cleaner" installation and eliminates the need for multiple wall-warts and adapter cables etc.