The Hanna Instruments in-Line pH and industrial controller is a wall-mounted two-in-one controller with a pH range of 0.00 to 14.00, two setpoints, the capability for two ground probes, and dual LCD screens. A pH controller is used in industrial control systems to calculate the difference between measured pH and a desired setpoint. The controller then adjusts the pH as needed using process control inputs. These controllers provide for two ground probes (sold separately) to avoid electrical noise and interference. The controllers display the current measurements on dual LCD screens.

A pH meter, also called a sensor or tester, is a device used to measure the acidity or alkalinity of a substance. A pH meter has either a portable or a benchtop body. Many portable meters are handheld devices. Some testers have an internal sensor, and may have a tip and body that fit inside of a container for measurement. A meter is commonly used in many different environments, from laboratories to field research and manufacturing facilities. Researchers, manufacturers, and hobbyists use a pH meter in aquaculture, agriculture, wine-making, and water-testing, and for scientific applications. Some pH meters may measure additional parameters such as dissolved oxygen (DO), conductivity (also called electro-conductivity or EC), temperature, total dissolved solids (TDS), salinity, resistivity, or oxygen reduction potential.

Hanna Instruments manufactures analytical instrumentation and supplies, including pH meters, electrodes, chemical reagents, and buffer solutions. The company, founded in 1978 and headquartered in Woonsocket, RI, meets International Organization for Standardization (ISO) standard 9001.