Developed to prevent potentially dangerous cross-connections in industrial applications, CEJN Series 347 nipples are noninterchangable with any other CEJN series couplings. The series is useful in applications with multiple access points for different media, such as breathing air, compressed air, and gas. The double shut-off series has a valved nipple. The special valve design of both the coupling and nipple provide an extremely high rate of airflow. Like most CEJN breathing air series, Series 347 offers one-hand-operated connection, an integrated safety feature that guards against unintentional disconnection, and a grip-friendly locking sleeve.