This is a Cejn Series 344 breathing air quick release coupling, couplings are manufactured from zinc plated steel / brass and nipples are manufactured from hardened zinc plated steel. This range has a maximum working pressure of 35 bar with a flow capacity of 1950 l/min. This coupling is valved which is closed when disconnected. These couplings are designed to prevent unintention disconnection, one hand to connect, and two hand to disconnect.
These fittings are designed to have an extremely high flow rate and are perfect for use in damp/wet and corrosive environments.