Glass, 'H' Type Potometer Cut shoot is attached to the side arm with tubing and the wide glass tube acts as the reservoir. Reservoir tube measures 6" long, and 3" wide with side arm. Capillary tube measures 7" Great for individual student use Suitable for individual student use, the cut shoot is attached to the side arm with tubing and the wide glass tube acts as the reservoir. Glass reservoir tube measures 6" long, 3" wide with side arm, and has a diameter of 0.75" Capillary tube measures 7" long with Bore measuring 1mm. When assembled, the potometer measures 14" in length.