A 8mm Quick Release Gas Hose Coupling. A 10mm o.d x 10mm o.d. (for 8mm/5/16" bore hose) brass Fulham nozzle hose connection.
By sliding back the knurled collar, one hose nozzle is released. As the coupling is hose-to-hose, it is useful for barbecue and patio heater assemblies. The body of the coupling is "valved" internally with the direction of flow towards the loose nozzle.