Telescopic tube and rod type convergence indicator is most common and widely used system. System comprises of two sub assemblies, the top assembly comprises of telescopic brass or steel rod with graduation in mm. The bottom assembly comprises of pipe assembly in it.
This rod can smoothly move through telescopic tube. The rod has marking in mm and cm. on its top end some times measurement marking on rod is replaced by a steel scale. An adjustable arrangement, locator is provided to adjust the initial measurement. The standard model is suitable for 3 meter cavity height but other heights are also available on request.
