A liquid level control with pneumatic switch is a pneumatic level switch. It is designed for horizontal mounting in a tank or vessel through threaded or flanged pipe connections. The buoyancy force of process liquid on a float causes the float to move with the liquid's surface. Float movement pivots a magnet into the field of a like-charged switch magnet. As the magnets repel each other, the switch magnet moves, actuating the switch. It is used in clean liquid, process vessel and skids applications.

Liquid Level Indicator is a standard feature on liquid filled transformer tanks, since the liquid medium is critical for cooling and insulation. This indicator is typically a round-faced gauge on the side of the tank, with a float and float arm that moves a dial pointer as the liquid level changes. It usually gives an audible or vibratory indication when a conducting fluid has reached a pre-set height. It is used to determine the volume content of liquid in vessels such as underground fuel.

Liquid Level Sensor acts as a switch. It works on the principle that when an unclad fiber is immersed in a liquid, the increased refractive index at the interface allows light to escape from the fiber. This enables a type of detection. The light from the input fiber, after total internal reflection at the prism surfaces is received by the output fiber. As the prism surfaces come in contact with the liquid, the condition for total internal reflection is violated, and some of the light escapes to the liquid. This results in a sharp decrease in the output.

Liquid Level Transmitters operate by mechanically exciting a primary sensing element made of a magnetostrictive material.