Safety couplings

On an ordinary coupling the plug comes free while the hose is still pressurised, and the hose whips back. A safety coupling disconnects in two steps: first the bore closes and the trapped pressure vents, only then does the lock release.That costs half a second and saves a smack on your hand or your face. On a hose reel or a long workshop hose this is the version you want, and on many sites it is now the only one allowed.