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.

Honeywell offers a line of analyzers, transmitters and dissolved oxygen probes. Products include DierectLine ppm and ppb transmitters, DirectLine Equilibrium dissolved oxygen probes, and a multiple input analyzer for measurement of pH, ORP, conductivity and dissolved oxygen.

Endress & Hauser offer digital amperometric dissolved oxygen sensors with measuring ranges of 0,001 up to 100mg/l. Applications include food, pharma, power, chemistry, water and waste water. Brand names offered include Memosens and Oxymax. Dissolved oxygen transmitters (in two and four wire configurations) and assemblies are also available.

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).