The Penis Cylinder contains a state-of-the-art air valve which allows quick release from the pump, while maintaining pressure within the cylinder. The cylinder is 9 inches long with a 2.25 inch opening. The cylinder is tapered for comfort and a flared base doesn't require a gasket for a perfect fit. The cylinder is made from ultra-clear polished acrylic. The hose is industrial-grade with a quick release air valve. The easily readable pressure gauge lets you measure consistent pressure. The grip is comfortable with a quick safety release nearby. Some men swear by the use of pumps as effective tools for increasing size while others think pumps have no lasting effect. Pumps can extend length while using, but the question is, will the penis return to original size after using? Unfortunately we do not have that answer and can not guarantee or be responsible for any results.