The radioisotope density meter ensures the fast determination of the density. Due to its structure, it can be applied to perform precisely bound or field measurements. The switches, which can be set to the appropriate rate according to demand, enable us to receive signals when changes occur, without constant observation of the device. The application consists of three items: the work case, including the radiation source; meter head attached to a pipe; and the display item. The display item contains the signal processing electronics, which ensures that the measured value is displayed and provides analog or digital signals for the control.