The Connector (CN, CR) valve is a check valve with a pipe nipple or connector housing. It is designed to be used in installations where a check valve with male pipe threads is required. The CN valve is adaptable for use as a low pressure relief valve or vacuum breaker by using the desired spring settings. Two valves used in combination make an excellent pressure vacuum vent. NPT threads are per ASME B1.20.1. Also available with ISO 7 “R” threads (CR).