The FEBCO 850 is an in-line design double-check valve assembly used to prevent contamination from backflow or back-siphonage.  It features an epoxy coated ductile iron body and NRS resilient wedge gate valve.  The maximum working pressure for the FEBCO 850 is 175 psi. FEBCO is one of the leading manufacturers of back flow devices and

A back flow device is used to prevent dangerous backflow in the water pipes caused by a sudden drop in water pressure. When such a drop occurs, water can reverse direction within the pipes, sending pollutants and contaminants back into the potable water supply. To prevent this from happening, back flow devices like pressure valves