Swichgage instruments are high-quality diaphragm-actuated, dial gauges for various with built-in electrical switches.These switches are used for tripping alarms and/or shutdown devices. The 20 and 25 series gauge mechanism is enclosed in a steel case coated to resist corrosion. A-Series gauges have a polycarbonate case and are sealed from the environment. All gauges feature a polycarbonate, break-resistant lens and a polished, stainless steel bezel to help protect these rugged, built-to-last instruments. The pointer acts as both an indicator and as one switch pole which completes a circuit when it touches the adjustable limit contact. Contacts have a self-cleaning motion to ensure electrical continuity. More compact, gauge-only models without contacts (known as Murphygage instruments) are also available.