High-density thermo-plastic construction.
With 1 in W frame for new construction or to replace old foundation vents. Aluminum louvers. Bestvents 315CGR Foundation Vent, 62 sq-in Net Free Ventilating Area, Thermoplastic, Gray Simple homeowner/DIYer snap-in installation, with color matched set screws for additional stability. Operates automatically without electricity, opens at 70 deg F, closes at 40 (approximately).