Amazon.com: EFIELD Washing Machine Outlet Box with Center Drain, 1/2 inch CPVC x 3/4 inch MHT (1/2"-Inch CPVC Connection), White (Regular) : Tools & Home Improvement
EASTMAN Quarter Turn Ball Valve C PVC Washing Machine Outlet Box in the Appliance Outlet Boxes department at Lowes.com
How to Clean a Washing Machine Drain | HomeServe USA
How to Choose a Washing Machine Outlet Box | Oatey