The Expander Pak adds additonal coverage to your Alto Professional Stealth wireless system. The easy-to-use Stealth Wireless system from Alto Professional replaces hundreds of feet of audio cable with a reliable wireless connection. Grow your Stealth Wireless system with the handy Expander Pack, containing two additional single channel receivers. Build Your Custom Stealth Wireless System The Stealth Wireless system quickly creates a robust, invisible connection from the output of your mixer to the inputs of your active loudspeakers. Using the Expander Pack, you can additional active loudspeakers to your array to create a larger system, or to provide multi-room coverage. There’s no need to snake, secure, or hide any cabling during set up. After the show, simply disconnect the system and be on your way—no more tedious cable coiling at the end of the night.