The valve is a connector that is implanted in the spermatic ducts with a rocker switch that can be toggled on and off. The valve switch can be felt and easily controlled with your fingers through the scrotum skin. The switch direction is simple to remember; to open the valve push the switch down toward your abdomen, from where the sperm cells would normally flow. This will push the part of the switch closer to your abdomen into the valve body. In addition to this you will also need to press the safety pin on the underside of the valve simultaneously.
To close the valve, simply press the switch down toward the testes, so that the part of the switch directed at the testes will be pushed down into the valve body. When closing the valve you do not need to press the safety pin. It would be sensible to keep both valve switches in the same position.