Glass, with side tubes, closed by hollow ground in glass
stoppers which when rotated can open or close the side tubes.
Size of U-tube excluding stopper.
Glass with inlet and outlet tubes, with ground in key stoppers
when rotated opens or close the oulet tube, height up to
outlet tube 125 mm, diameter 32 mm and capacity 100 ml.
Glass, with inlet and outlet tube at the top, ground in stopper
when rotated opens or block the inlet and outlet tubes. An
external tube takes the gas to the bottom. Overall size :
