A gauge is a measuring instrument used to determine the size, amount, level, pressure, or other physical quantity of a substance or system. Gauges come in many types depending on their function—such as pressure gauges, temperature gauges, thickness gauges, fuel gauges, and depth gauges. They are essential tools in various industries including manufacturing, automotive, aerospace, HVAC, and engineering, providing accurate readings for monitoring and control. Gauges can be analog (with dials and needles) or digital, and are designed to withstand specific environmental and operational conditions.