Prevost ‘Orange’ Push Button ISO4414 Safety, Zero Pressure Disconnect Couplings.
These would normally be fitted on a compressor outlet or pipe work to protect the hose in front of it i.e. every time the hose is disconnected, it has no pressure in it so cannot cause an accident. This is compliant to ISO4414 EN983. There is also an 8mm hose tail version which can be fitted to the working end of the hose to add protection when using extension hoses.
An added benefit is a two year ‘leak free’ warranty when replacing coupling and plug. This effectively pays back the extra cost in not having the compressor running to cover leaks.