An implantable device controls the movement of fluid to an inflatable portion of a gastric band. The implantable device includes a body. The body has an inlet, an outlet and a valve seat positioned between the inlet and the outlet. The body defines a fluid passage from the inlet to the outlet. The implantable device also includes a diaphragm. The diaphragm has one or more edges coupled to the body. The diaphragm is made of an elastomeric material and capable of being moved between a closed position that blocks the valve seat and does not allow the fluid to move from the inlet to the outlet and an open position that does not block the valve seat and allows the fluid to move from the inlet to the outlet.
