Series C300, C300N Double Check Valve Assemblies prevent the backflow of pollutants that are objectionable but not toxic, from entering into the potable water supply. Its compact housing consists of two independently operating tri-link check valves, two shutoff valves and four test cocks. It features a stainless steel housing and sleeve and is 70% lighter than traditional designs. Series C300, C300N is designed for non-health hazard applications and may be installed under continuous pressure service to protect against both backpressure and back siphon age. This Series is used primarily on fire sprinkler lines when it is necessary to monitor unauthorized use of water.