Challenger Series 4310 Blower Pro Paks from National Vacuum Equipment have been updated with a new enclosure design to improve the ease of maintenance while dramatically decreasing sound levels. An internal ballast silencing system coupled with a number of exhaust silencer options yields a package that meets the needs of end users. They are available in frame- or top-mount models, with multiple drive options. 800/253-5500; www.natvac.com