A weight control device that is implantable with an endoscope and that is adapted to form a gastric outlet obstruction in a patient's digestive tract, the weight control device comprising: a first bulb, a second bulb with a circumference less than a circumference of the first bulb, and an intermediate portion with a circumference less than the circumference of the first and second bulbs (15, 20) that is adapted to reside within the patient's pyloric valve when the device is implanted, wherein the first bulb, the second bulb and the intermediate portion collectively define an inflatable body; the body further having at least one internal central passageway extending through the first and second bulbs (15, 20) and the intermediate portion; and, wherein chyme exiting the patient's stomach passes through the internal central passageway to reach the duodenum; characterized in that the weight control device further comprises: an internal valve assembly having both a valve body and a stem, the valve body having one of a one-way valve and a two-way valve, the internal valve assembly extending inward from an off-center position of the outer surface of the body to the first bulb, the internal valve assembly providing delivery of an inflation fluid to the first bulb; wherein the first bulb, the second bulb and the intermediate portion are formed from one material; and wherein the intermediate portion is formed with a greater rigidity than the rigidity of the first and second bulbs (15, 20). a first bulb, a second bulb with a circumference less than a circumference of the first bulb, and an intermediate portion with a circumference less than the circumference of the first and second bulbs (15, 20) that is adapted to reside within the patient's pyloric valve when the device is implanted, wherein the first bulb, the second bulb and the intermediate portion collectively define an inflatable body; the body further having at least one internal central passageway extending through the first and second bulbs (15, 20) and the intermediate portion; and, wherein chyme exiting the patient's stomach passes through the internal central passageway to reach the duodenum; characterized in that the weight control device further comprises: an internal valve assembly having both a valve body and a stem, the valve body having one of a one-way valve and a two-way valve, the internal valve assembly extending inward from an off-center position of the outer surface of the body to the first bulb, the internal valve assembly providing delivery of an inflation fluid to the first bulb; wherein the first bulb, the second bulb and the intermediate portion are formed from one material; and wherein the intermediate portion is formed with a greater rigidity than the rigidity of the first and second bulbs (15, 20). an internal valve assembly having both a valve body and a stem, the valve body having one of a one-way valve and a two-way valve, the internal valve assembly extending inward from an off-center position of the outer surface of the body to the first bulb, the internal valve assembly providing delivery of an inflation fluid to the first bulb; wherein the first bulb, the second bulb and the intermediate portion are formed from one material; and wherein the intermediate portion is formed with a greater rigidity than the rigidity of the first and second bulbs (15, 20).