ABB offers four-wire dissolved oxygen analyzers for measurement of ppm levels, including single/dual input analyzers, single input analyzers, and dissolved oxygen monitor systems. ABB also offers dissolved oxygen sensing systems for high-level ppm measurements for rivers and sewage treatment.

Global Water Instrumentation offers dissoved oxygen instruments, such as sensors (water oxygen level measuring devices), industrial transmitters, optical sensors (for measuring dissolved oxygen concentrations in liquids), meters, probe kits, portable meters and handheld meters.

The Vernier dissolved oxygen probe has a range of 0 to 14 mg/L (ppm). It has built-in temperature compensation, so you can do your calibrations in the lab and then make measurements outdoors without the need for recalibration. Accessories available include DO filling solution, calibration solution, polishing strips, water depth samplers, membranes for DO sensors, and electrode support.

Yokogawa offers dissolved oxygen analyzers in two and four wire configurations. Their oxygen sensors are used in water treatment plants, such as sewage treatment, potable water treatment, and effluent activated sludge processes. Yokogawa also offers the Hamilton dissolved oxygen sensor designed to meet the severe requirements of the Biotechnology industry.

Geo Scientific offers dissolved oxygen sensors that produce a millivolt output proportional to the oxygen present in the medium in which it is placed. Other products include submersible water quality transmitters that utilize integrated preamps and an isolated 2-wire, 4-20 mA transmitter.

pHionics offers dissolved oxygen sensors and transmitters for water quality monitoring and control. Their STs6020C is an isolated series 2-wire, 4-20 ma dissolved oxygen transmitter. The  STs6020TC is also an isolated 2-wire, 4-20 ma dissolved oxygen transmitter but comes with an additional temperature output channel. The STs6020B has 0.00 - 2.00 vdc output and is self-powered with internal AA battery. The STs6020V also has 0.00 - 2.00 vdc output but is powered by an external source (such as a 12 volt battery).

AMI manufactures over 27 different types of analyzers, including Percent (%) Oxygen Analyzers, and Trace (ppm) Oxygen Analyzers and Oxygen Sensors. Analyzers are available in portable and permanent mount versions. The hydrogen sulfide (H2S) gas analyzers include measurement ranges from 0-2000ppm. All products meet area classification requirements ranging from general purpose to Class I, Div. I, Groups B, C, D.