The Cadillac of Pump Systems! Cylinder is made of clear Lucite with a quick-release connector at the top that maintains the vacuum until you twist the connector. The base of the cylinder is flared and smooth for a gasket-free seal. Cylinder averages 9 inch to 10 inch in inside length. Dimension indicated is inside diameter. For use with Boston Pumps. Includes one 3 inch Cylinder ONLY. Made in the U.S.A by Boston Trading Company.