For measuring the pressure of gases. Suitable for moderate pressures. Consists of a borosilicate glass U-tube, diameter 25mm and 50cm high, open at both ends. Has one rifﬂed arm for easy connection to rubber tubing. Mounted on a wooden board ﬁxed on a metal stand. A metric scale is ﬁtted between the arms of the tube. It is recommended to use colored water for greater visibility in a lecture hall.