The function of this ventilator is to keep the inside and outside prsssure to be balanceable , even if the inside temperature is below 00, so as to ensure free opening of the door .
With a temperature controller inside the window , which keep the windows temperature within 200-400, then guarantee fluent ventilation .
With a stainless steel mesh , which prevent the insect from entering .
Groove on the vents , avoid the inleakage of water.
AC 220V or AC 110V are on your option