Abstract: A hand tightenable connector provides a high pressure seal between a first element and a second element. A first female element includes a recess for supporting a compressible O-ring and a second male element includes a ferrule which deforms the O-ring in the recess when the male and female elements are mated. The ferrule abuts against the surface defining the opening of the O-ring recess so that a high pressure seal is effected between the first and second elements without severely distorting the O-ring. The connector may be used to couple various components of a high pressure fluid delivery system such as are found in a jet cutting system.