The Wika low pressure differential pressure gauge is designed to measure dry, clean non-aggressive gases and air. This instrument is ideally suited to measure differential pressure in filtration systems, pressure monitoring for HVAC, air handlers and ventilation systems and for pressure monitoring of clean rooms, gas scrubbers and dust collection systems. 4-1/2-inches diameter. Case: high-impact polycarbonate. Wetted parts: silicone rubber, polycarbonate. Window: polycarbonate. Dial: white aluminum. Pointer: black aluminum. Accuracy: + 3 percent of span. Mounting: 3 self-tapping mounting screws (standard). Applications: for dry, clean, non-aggressive gases, usually air, fan and blower monitoring, differential pressure monitoring in filters and overpressure monitoring in cleanrooms.