These are white plastic louvered air intake caps to be used with round duct, suitable for use with heat and energy recovery ventilation systems. The louvers are fixed in place, insuring intake air can enter unobstructed. They have a one-piece molded screen, preventing rodents such as mice and large insects from entering, and are secured with four corner screws (not included).
Manufactured by: Imperial Manufacturing
Boflex 4 inch White Intake Grille PA-4W Product Reviews