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.

Ion specific electrode meters are millivolt meters that interface with ion selective electrodes (ISEs).

Dissolved CO₂ instruments are analytical devices that measure the amount of carbon dioxide (CO₂) dissolved in a liquid sample such as water.

Gas sensors interact with a gas to initiate the measurement of its concentration.

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

Water quality testing instruments are used to test water for chemical and biological agents, and to measure variables such as clarity and rate of movement.