The Pendulum is mounted on antifriction bearings. It has two starting positions, the upper ane far Charpy and the lower one for Charpy & the lower one for Izod testing. On release, the Pendulum swing down to break the specimen and the energy absorbed in doing so is measured as the difference between the height of drop before rupture & height of raise after rupture of he test specimen and is read from the maximum pointer on the dial scale.