Marsh Instruments Bimetal Thermometers are heavy-duty instruments for temperature indication in dual scale ranges from -50° to 1,000°F (-40° to 525°C). Series “L” Bimetal Thermometers include an easy-to-read dual scale, fast response, and accurate temperature indication. The hermetically sealed case is resistant to shock, vibration, dust, and moisture. The bimetal sensing element provides an accuracy to within 1% of scale. An external adjustment screw on the back of the case provides convenient reset and field calibration. Built-in over-range protection is a standard feature.