Abstract: An underwater receptacle has a pressure balancing arrangement that balances he underwater force that tend to hold a receptacle and its mated plug together. The pressure balancing arrangement also relieves the air pressure formed between the insert discs of the plug and receptacle when connecting the insert discs respective electrical pins and sockets. This is achieved by moving the volume of air formed between the discs on connecting the respective components. The volume of air passes through the receptacle disc and operates a piston to form a chamber for holding the volume of air. The other side of the piston is exposed to sea pressure. This forces the volume of air back into its original position and eliminates a vacuum suction by neutralizing the pressure on the plug when disconnecting the plug from the receptacle.