Guan Seng Air Ventilation GSAV is an authorized dealer of Altra-Air Fans by Envira North Systems Ltd. Envira North systems Ltd was established since 2003 by Dan Lambert in Canada. GSAV is pleased to introduce the new Altra-Air Fans with WhalePower's Technology. These Fans have been upgraded from the conventional HVLS fans in the form of it's five-bladed design in addition to incorporating the Tubercle Technology from Whalepower which is giving a 20 percent of efficiency boost.