Dissolved oxygen meters are analytical instruments that are used to measure the amount of oxygen dissolved in a liquid sample

Dissolved oxygen sensors are used to measure the amount of oxygen dissolved in a unit volume of water. In water quality applications, such as aquaculture (including fish farming) and wastewater treatment, the amount of dissolved oxygen (DO) must be kept high

Gas sensors interact with a gas to initiate the measurement of its concentration. The sensor then provides output to an instrument to display the measurements

Level sensors are used to detect liquid or powder levels, or interfaces between liquids. There are two basic level-measurement types: continuous and point or multi-point

Temperature instruments use contact or noncontact methods to measure temperature. Products include dial, digital, industrial and laboratory thermometers; temperature probes, indicators, and sensors; RTD elements and transmitters; and thermistors, thermocouples, thermopiles, and thermal switches. 

Sensor chips are dies incorporating semiconductor circuit elements that are used to convert changes to some physical parameter to an electrical signal

Gas and air instruments detect, monitor or analyze gases present in an environment.

Opacity sensors and instruments measure the amount of light transmitted through a sample

Gas generators provide an onsite supply of gas, vapor or humidity (water vapor) eliminating the need for delivery in gas cylinders.

Ion selective electrodes measure the potential of a specific ion in solution. This potential is measured against a stable reference electrode of constant potential.

Water quality photometers and colorimeters are ion-specific computer-interfaced probes designed to determine the concentration of a solution from its color intensity.

Combustion analyzers and flue gas analyzers measure the gas content of emissions in order to monitor the combustion efficiency of fuel-burning equipment.

Specialty or proprietary products related to environmental sensors and instruments

Thermistors are thermally-sensitive devices whose electrical resistance varies with temperature. Unlike RTDs and thermocouples, thermistors do not have standards associated with their resistance vs. temperature characteristics or curves.

Dissolved CO₂ instruments are analytical devices that measure the amount of carbon dioxide (CO₂) dissolved in a liquid sample such as water. They typically include a submerged probe that is covered by a thin organic membrane.