... performance 4.clean fan design 20W,25W,30W solar attic fan,solar ventilation fan ,solar powered exhaust fanThe Specificaton :1. Minimize backpressure of ... condition.The characters:1. High efficiency poly-silicon solar panels.2. Brushless DC motor.3.90 angle adjustable panel bracket.4. ... or 5 years4. Thermostat 3 years. 20W,25W,30W solar attic fan,solar ventilation fan ,solar powered exhaust fan