Barn Air Inlet Roof/Ceiling Ventilation Window

Barn Air Inlet Roof/Ceiling with dual sides or four sides ventilation window, opening automatically in different size according to negative pressure change. 

• Dual sides ventilation window, opening automatically in different sizes according to negative pressure change.
• Resist high temperature and cold, high intensity, easy to install, long useful life.
• Outline border,blade make by engineering plastics. 
• Foam at the bottom, foam board thickness 20mm.