The use of a cylinder along with a head pump is used to create a level of vacuum that will stretch and enlarge tissue. The state of the art connector/air valve allows pump to disconnect from the cylinder while maintaining exact pressure chosen. The 9.5in X 2in cast clear Lucite cylinder is specially flared on the bottom to obtain comfortable suction. The hand held industrial grade pump is heavy duty but also lightweight. The brass air chamber and piston have dependable neoprene valves. This unit works equally well in air or water. The Boston Pump Works... hand made in the United States of America!