A connector adapted for forming a fluid flow pathway therethrough by connection with a reciprocal connector, wherein both the connector and the reciprocal connector each comprise a fluid flow passageway part (11A) defining a fluid flow opening, a socket part (12A) located upon the fluid flow passageway part adjacent to the fluid flow opening, a plug part (13A) located upon the fluid flow passageway part adjacent to the fluid flow opening and spaced from the socket part in a direction crossing the fluid flow opening, wherein the socket part of the connector is configured to receive therein the plug part of said reciprocal connector to connect thereto such that the fluid flow opening of the connector is aligned in register with the fluid flow opening of the reciprocal connector and, a closure part (14A) arranged to openably close the fluid flow opening of the connector and to receive an urging force from said received plug part of the reciprocal connector thereby to be displaced in a direction crossing the fluid flow opening to uncover the fluid flow opening such that the connector is thereby connectable to the reciprocal connector with respective fluid flow openings in fluid communication.