Functionality.WHK washing machine box with water hammer arrester can reduce hum noise when you running your portable washer in laundry room,and provide a safe,quick water supply installation for washing machines, water supply shut-off access.the laundry box provides a recessed space for your supply valves. Features. The design of PEX laundry box is for recessed residential applications features a center drain for easy drainage,Pls Note that the PEX Connector( F1807) is Fits PEX B pipe,DON'T use to connect PEX A pipe,