One Way Aluminum Insulvent I

The spun heavy gauge aluminum (.051") Insulvent is a low cost method for venting all types of insulation. Insulvent I offers a special one-way silicone rubber valve to prevent moisture from re-entering the roofing system. Flange may be primed. Overall height 8-1/2", Base opening 4", Flange diameter 10-3/4". Recommended spacing: 1 per 1000 sq. ft.