Dometic/Sealand's VacuFlush JW 24 volt vacuum generator pump assembly kit (311230) comes with all components necessary to rebuild or replace your pump, including duckbill valves and O-rings. This kit may not be available in all areas. Works with Vacuum Generator 4 (VG4). Please call Environmental Marine for more information.
Link to VG4 diagram: https://www.environmentalmarine.com/vacuum-generator-4-vg4/