Plug connector and connector assembly

A connector assembly, comprising:

• a plug connector comprising:
• a terminal module;
• and
• a connecting module comprising:
• a cannular shelter defining a center line and having a bump arranged on an outer wall thereof, wherein the terminal module is inserted into the shelter;
• a fixing nut screwed onto one end of the shelter;
• a socket holder having a ridge arranged on an inner wall thereof, wherein the shelter is inserted into the socket holder, and the ridge is disposed between the bump and the fixing nut for enabling the socket holder to move relative to the shelter between a first position and a second position along the center line, and wherein the shelter, the fixing nut, and the socket holder define an accommodating space;
• and
• a spring arranged in the accommodating space, wherein two opposite ends of the spring are respectively abutted on the ridge and the fixing nut for providing an elastic force, and wherein the elastic force enables the socket holder to move from the second position toward the first position;
• and
• a socket connector detachably combined with the plug connector,
• wherein the socket connector comprises:
• a mating terminal module;
• and
• a coupling module comprising:
• a cannular mating shelter having an inner flange and a receiving trough spaced arranged on an inner wall thereof, wherein the mating terminal module is inserted into the mating shelter;
• and
• an O-ring disposed in the receiving trough and arranged on between the inner wall of the mating shelter and the outer wall of the shelter, wherein the internal diameter of the O-ring is smaller than the external diameter of the shelter for establishing a seamless connection between the O-ring and the shelter.