Doozertubes are audio communication devices devised and built by the Doozers, introduced in the 2020 Fraggle Rock: Rock On! shorts. The Fraggles use them to communicate with each other from around Fraggle Rock. They even manage to make their way to Outer Space with the distribution help of Uncle Traveling Matt (as well as a Doozer mishap).
The Doozertube system continued to be used in Fraggle Rock: Back to the Rock, notably employed in the episodes "The Legend of Icy Joe" and "All of Us." The Fraggles also used the system to communicate with Uncle Matt during his appearances in the 2022 Macy's Thanksgiving Day Parade.