Filtex and AirVac have historically been very common brands of built-in vacuum power units in the Chicagoland area. In this video, I use a selection of traded-in units to illustrate the evolution of the brands and designs from the 1970s (parent company: Natter Manufacturing) into the 1980s (Fairchild Industries, later Music & Sound), 1990s (M&S Systems, subsidiary of Nortek), and 2000s (M&S, division of Linear). While Linear has totally exited the vacuum business as of several years ago, we still regularly service and perform upgrades to these systems.