These are multipurpose gauges for severe industrial service where ruggedness is required, especially when vibration or pulsation is a factor. The case may be liquid filled to reduce the effects of pulsation or vibration and to protect from hostile environments.
The movement has high and low mechanical stops at 20% above and below the scale. As a stanard feature the gauges are supplied with an internal pulsation restrictor. Both the 2½" and 4" gauges have ±1% full scale accuracy.