Instruments manufactured to control the electrical operation of compressors, pumps, presses, hydraulic and pneumatic equipments, chemical and petrochemical plant. In the event of leakage or break of sensing element, the operator is protected by a solid baffle wall placed on the instrument front and by the rear blow out wall. The contacts open or close the circuit depending on the position of the indicating pointer and they are adjustable over the whole range. For application on severe working conditions, such as rapid and frequent pressure change, vibration and pulsation, they are manufactured with the case liquid filled. The filling drastically reduce the effects of such factors as well as those caused by the corrosive atmosphere, making longer life and better performances of the pressure gauge and their electric contacts. They are also available with inductive contacts intrinsically safe.