The Koolmax® Exhaust Fan is a 57″ fan that features the direct drive, permanent magnet motor which is high energy efficiency. The housing and frame is made of fibreglass preventing rust and corrosion in any environment. And the Exhaust fan has an additional includes sealing doors that seal out air and light when closed, the sealing door is ( patented pending) very good for cold temperature climate, with which can have a very air tight function to prevent heat emission during winter seas...