1Applicable Models: Vacuum breaker kit is replacement for Dometic 300 321 320 310 500 100 200 500H 700 800 900 1000 2000 3000 4000 toilets with hand sprayers. 2OE Number: The part number for reference is 385230325. Please confirm whether it is consistent with the OE you need to avoid wrong buying and other problems. 3Prevent Backflow: The vacuum circuit breaker kit prevents waste water from flowing back from the Rv toilet back into the freshwater supply system. 4Easy to Install: Installing the toilet water valve module is a very simple process. Simply remove the damaged or old toilet valve and install the new valve in its original location. Don't forget to switch off the main water supply before installation. 5Space Increasing: Toilet hand spray vacuum breaker have extended tube, adding space when connecting the toilet water pipe, convenient for daily use.