It is a fact that fortification-class military units have gained great importance in wartime. These engineering troops undertake various tasks on the battlefield, such as the construction of military structures, trench digging, mine laying and logistics work.  During the construction works carried out on the battlefield in the 19th and 20th century, spirit scales provided great convenience for making the correct horizontal and vertical adjustments. These simple but effective measuring instruments would support the successful activities of the fortification units. The product in our museum is a historical object used by the military class. According to the information written on it, it belongs to the 3rd Battalion Fortification unit of Kayseri. The patriotic soldiers of Kayseri, who actively participated in the calls for mobilization and the provision of soldiers in the Wars of the National Struggle, had shown superior sacrifices according to the needs on the important fronts where the wars were continuing. Although there is no clear information about which front this product was used, Kayseri fortification is an important historical evidence that testifies to the fact that the class also participated in these wars.