The Guillemin-coupling is a symmetrical system and apt for a large variety of applications. Its success is mostly because of the form, which enables perfect and easy closure. De symmetrical half couplings are tightened by turning the locking ring a quarter when it grips behind the lugs. The ensure even more tightness a Guillemin wrench can be used to turn the locking ring even further.
On fixed installations often is chosen for a half coupling whithout a locking ring, seen only one locking ring is needed to tighten 2 couplings together.
In some cases it is hard to couple a hose. In such a situation there can be chosen for a Guillemin coupling with a locking ring, but without the lugs.