The instrument consists of a wooden box with lid and two-hook closure, with internal shapes for housing the parts of the instrument, a cylindrical graduated glass beaker and a foot equipped with four spring strips that enter the rubbing bell . There are also a series of copper cylinders open at the bottom that act as a combustion chamber and a bell formed by a cylinder open at the bottom, with a series of holes at the lower edge and surmounted by a tap tube. Determines the calorific value of fuels for industrial purposes.