Inline quick action coupling units are designed to be fitted to one length of hose, the coupling pin is attached to a second length of hose. This allows for connection and disconnection of one hose from another hose without the use of spanners. The coupling unit and pin meet ISO 7289 and the double 'O' ring design ensures no leakage. It is important to note that the quick action coupling units offer no protection against flashbacks. Flashback arrestors should be fitted in oxygen/fuel gas applications.