The guide is constructed similar to a cardboard toolbox in 3 parts: the outer shell on which are diagrams of various structures (as in the pictures), inside the various structures there are windows in which the result of calculating the thickness of bolts or the thickness of the walls of pipes is displayed according to the selected matter. Inside the shell there are two booklets of tables and explanations, each table refers to a different measured object, such as the thickness of gas pipes. The units of measurement are in English inches and centimeters at the same time. The ruler is written in Hungarian and was made in Hungary by Kokeny Károly in Miskolc.