The Weida Prainsaver Tank is a rain water filter system that addresses consumers' water-saving needs. Featuring a buil-in flush diverter, the tank prevents an initial 25 liters of rain water run-off containing fine debris, from entering the tank. Once diverter. Rainwater is then diverted to the Rainsaver Tank. The first flush diverter will then reset itself by slowly draining off the initial rainwater and debris thru the drainage pipeline, after which it will be emptied and ready for the next rainfall.