AUTO-ŻAGIEL-SPORT
Check valve with two 19 mm hose connectors. The duckbill valve blocks the return of waste (gray / dirty sewage water).
Vetus company. The installation kit consists of:
check valve with mounting brackets
two 19 mm connectors
for a 19mm - 3/4 inch hose (D - drawing below))
very durable, strong NYLON
rubber seals and valve diaphragm
You are bidding on one set as in the photo below. On another auction, a valve with 25mm connectors.