The double disc check valve is built with stainless trim to give years of trouble free operation and to ensure compliance to NSF61 or Annex G standards. The double disc check valve can be installed in either horizontal or vertical pipelines that carry clean water or air. This valve is not intended to carry fluids containing solids such as raw sewage or wastewater. This valve is not suited for fluids that contain hazardous gases. The double disc check valve is designed to provide flow in the direction of the arrow marked on the outside nameplate, and instantaneously close upon sensing flow reversal. The nameplate will also indicate valve size, model number, working pressure and materials of construction.