An improved connector assembly is disclosed wherein end segment portions of a male plug have increasing cylindrical wall cylindrical wall diameter from the outer-most segment to an intermediate segment to an inner segment. The female receptacle has its female receptacle dimensions arranged to accept the male plug such that increasing cylindrical wall diameters exist from its outer-most segment to an intermediate segment to an inner-most segment. The increased diameters enhance the sealing with a strong and sustainable sealing pressure wherein coupling forces between the male plug and female receptacle are minor until the end of the insertion of the male plug into the female receptacle.