VENTURI APPARATUS For demonstrating Bernoullis principle that any restriction in fluid flow results in increased speed and decreased pressure. Comprised of borosilicate glass tube 18cm (7in) long and 18mm ( 3/4in) in diameter with a constriction in the centre and three vertical openings in different sections. Includes three glass manometer tubes and rubber connecting tubes for measuring pressure at three locations. Ends are flared. Qty :