What type of gauge gives readings of liquid contents at various levels?

The variable gauge is designed to measure and indicate the level of liquid contents within a container at various points. It operates by utilizing a mechanism that adapts to changes in the liquid level, enabling it to provide continuous readings rather than a single fixed measurement. This adaptability makes it particularly useful for applications where the liquid level may fluctuate, such as in tanks or reservoirs.

In many scenarios, a variable gauge can be mechanical or electronic, incorporating technologies like floats, sensors, or sight glasses that respond to the liquid's surface. This capability is essential for fire investigation technicians who need to understand the presence and quantity of flammable liquids in storage tanks or containers.

Other types of gauges, such as fixed level gauges, typically indicate whether the liquid is at a specific level rather than providing a range, while pressure gauges measure the pressure inside a system rather than liquid level. Digital gauges may also represent various data types but are not specifically designed to indicate levels at multiple points of liquid contents compared to variable gauges. Thus, the variable gauge is the most suitable answer in this context.