PV400 RV Plumbing Vent Carded Mud Dauber Screen by JCJ®. 1 Piece. Round. For "4 Prong" Plumbing Vent. Made of heavy rust-resistant stainless steel. Come with tension springs & installation tools. This product is made of high-quality materials to serve you for years to come. Designed using state-of-the-art technology and with customers in mind. It will meet your needs and deliver great quality at an affordable cost.