Negative pressure pulls back a frictionless Styrofoam baffle to provide direct access of fresh air into your barn. Open wide when plenty of air is needed, flow adjusts automatically to protect animals during cooler periods. Insulated hinged cover can be closed tight in cold temperatures or adjusted to any degree for proper air distribution. Counterweight allows for fine control. (Also available in black.)

• Model No.: WI-800  RSO = 14" W x 11" L
• Model No.: WI-1200  RSO = 22" W x 14" L
• Model No.: WI-2400 RSO = 45.5" W x 14" L