Shurflo’s 4009 series fresh water pump design was created with a unique one-piece diaphragm and internal by-pass, assuring long life and top performance. The 4009 series pump is constructed for high flow demand, low noise and no rapid cycling. The 4009 series fresh water automatic demand pump is super quite, thermally protected and can run dry without damage. Note: A filter must be installed with the 4009 pump in order to validate warranty.