Abstract A method for connecting a relatively rigid member and relatively flexible member by employing ultrasonic energy, characterized in that an annular axial projection on the rigid member is softened by the application of ultrasonic energy thereto and is simultaneously deformed around a corresponding annular transverse flange on the other member to permanently bond said members together to define a hermetically sealed joint. The invention also relates to the resultant product which comprises an entry spike-drip barrel adapted for connection with a container for parenteral solutions, said device including a relatively rigid spike member that is bonded by a hermetic seal with a relatively flexible drip barrel member.