When the piston gear depressurizes the area inside the cylinder above the elevator car, the car is then lifted by higher atmospheric pressure below the car. The inside of the car always remains at atmospheric pressure. As air pressure is lowered above the car, the car is lifted. A valve regulating inflow of air in the upper part of the shaft controls the pneumatic depression and enables descent. When the valve lets in air (at atmospheric pressure) into the low pressure chamber, the car will safely lower to the desired level. This valve also controls the speed of the car. The lower part of the shaft is open to ensure free entrance of air at atmospheric pressure. The air suction process simply consists of a suction device that sets the difference in pressures between the atmospheric and that inside the shaft, limited by the piston, the side walls and the upper end. The car has locking devices included in the interior of the shaft to stop the car at the upper and lower limits of travel. For better safety conditions, a braking system located on the roof of the car activates in case the tube above the car has a sudden return to atmospheric pressure. The braking system is made up of either a diaphragm or piston. Safety Controls: The upper chamber has a pressure switch which will detect instant re-pressurization of the upper chamber. If this unlikely incident were to occur, the elevator will brake within 2 inches on free fall. If a sudden power outage occurs while the elevator is being used, the elevator car automatically descends to ground floor at a slower than normal speed because there is no air being induced into the upper chamber (as is the case when power is on). Each elevator comes with an alarm system, emergency ventilation, and door safety switches. The doors can not be opened while the elevator is in operation. Each car comes with a telephone base mount and wiring from the car to the elevator controller located in the pump box above the cylinder.