Oatey? Sure Vent? Air Admittance Valve Wall Box are designed for use with Air Admittance Valves requiring recessed installation. When combined with 6 or 20 DFU air admittance valves, the Oatey Sure-Vent AAV wall boxes are a convenient solution for recessed installations. The high-impact polystyrene construction accommodates 1-1/2" to 2" adapters through the box opening while the textured grille faceplate conceals the AAV, providing a professional looking finish.