A coupling device for joining together two fluid conduits and for providing fluid access to fluid in the fluid conduits. The device comprises a first coupling member which is adapted to be connected to one of the fluid conduits and a second coupling member adapted to be connected to the other fluid conduit. The first and second coupling members are adapted to be connected together to define an axial fluid passage therethrough between the two fluid conduits. An elastic member having an axial fluid opening therethrough is interposed between the first and second coupling members and the axial fluid opening thereof is axially aligned with the axial fluid passage defined by the first and second coupling members. Connecting means are also provided for connecting the first and second coupling members together to compress the elastic member between the first and second coupling members to seal the axial fluid passage. Also, at least one of the first and second coupling members includes an opening therethrough adjacent to the wall of the elastic member whereby selective fluid communication with the fluid in the fluid conduits can be obtained through the wall of the elastic member.