How the stainless steel couplings installation?
Step 1: loosen the screw of the coupling, then separate the rubber gasket from stainless steel ring
Step 2: let the fitting set in rubber gasket, meanwhile the pipes in stainless steel ring
Step 3: fix the pipe in rubber gasket
Step 4: fix the stainless steel ring on rubber gasket
Step 5: tighten the screw with screw driver or wrench
See attached attached picture more clear.