The rigid black cylinder in the center has a tube attached to it to fill the assembled unit with warm (40 to 45 degrees Celsius) water. The cone-shaped rubber liner above is inserted into the cylinder and the ends are folded back over the cylinder and held in place with rubber bands. Warm water is injected into the space between the cylinder and the liner, and the tube is clamped off. The centrifuge tube is connected to a rubber funnel, which in turn is connected to the artificial vagina itself.
Smith MC (2006)