Polaris QT Blowers are every bit as powerful as they are quiet - in fact they're the quietest on the market. Polaris also offers a full line of metal residential blowers. With rugged all-steel construction, Polaris Metal Blowers are an industry standard. Both models include a patented thermal relief valve that automatically compensates for temporary rises in temperature. The blower motor never gets hot enough to reach the shutoff point which means longer, more relaxing, uninterrupted service.