This can double window fan draws in fresh air from the outside or exhaust stale air from inside. Or due to the exhaust and draw out as it can do both simultaneously. The temperature at the fan on and off according to a preset temperature level, plus three fan speeds for each unit is adjusted to its terms. Designed to fit double-hung windows, casement and vertically, the fan comes with a built-in 7 inch scale and the second stretch. 3 - inch split to custom fit it in windows 24-37 inches wide, and because the plastic is lightweight, you can move it easily from room to room fans, a six-inch and 8 -.1/2 diameter. The unit is 12-1/4 inches high and carries a full three year warranty against defects.

Twin Window Fan