The product is highly durable and easy to use How to Install Secondary Venting Systems - Air Admittance Valves (AAV Oatey Plumbing Vent Cover 3" Mushroom Vent - Marine Sanitation & Supply Stainless Steel Mushroom Vent Cap The Oatey Mushroom Vent Cap is made of high-impact PVC and requires no assembly. It includes 3 hex-head bolts for ease of installation. The fully assembled... The product is manufactured in china Oatey 43805 PVC Mushroom Vent Cap, Each. Free shipping; Free 30-day returns Material of Construction Plastic, For Use With 3 or 4 Vent Stacks., Sold as 3 Pack.