Pro-Oceanus Systems, Inc.
Manufacturers of Ultra-Stable dissolved oxygen, nitrogen and total dissolved gas sensors.
http://www.pro-oceanus.com/

Pro-Oceanus Systems, Inc.
Manufacturers of an Ultra-Stable line of dissolved oxygen, nitrogen and total dissolved air sensors.
http://www.pro-oceanus.com/

PreSens Precision Sensing GmbH
Optical sensors and microsensors for dissolved oxygen, oxygen in dry gases and temperature to measure through glass and non-invasive.
http://www.presens.de/

DMP Ltd
DMP Ltd sells instruments for gas phase concentration measurement, gas blending and mixing, mainly for oxygen, hydrogen, carbon dioxide and humidity. Dissolved gas analysers are produced for chemical industry, mainly for oxygen and hydrogen.
http://www.fugatron.com/

Engineered Systems aqnd Designs
ESD manufactures instruments for measuring pH, conductivity, turbidity and oxygen. Instruments include portable and bench top meter configurations. Other items: oxygen controllers, x-ray calibration equipment, electrodes and sensors.
http://esdinc.com/

Strathkelvin Instruments
Strathkelvin Instruments is the world's leading supplier of precision respirometry and dissolved oxygen instruments for biomedical research.
http://www.strathkelvin.com/

ElectrodesDirect.com
ElectrodesDirect.com is a worldwide direct supplier of pH, ORP, Conductivity, Dissolved Oxygen, Ion Selective, and Biotechnology Electrodes and Assemblies. We can replace nearly any process or lab electrode with a high-quality electrode that fits your existing meter or transmitter - at factory prices.
http://www.electrodesdirect.com/

LTH Electronics
LTH offer a range of Contacting and Electrodeless Conductivity, pH, Redox, Dissolved Oxygen, Suspended Solids and Turbidity, Level and Flow instrumentation and sensors and a range of accessories for process applications
http://www.lth.co.uk/

Sentek Limited
Sentek manufacture Electrochemical Sensors for pH, Conductivity, Dissolved Oxygen and Ion Specific Electrodes. UK based specialising only in the production of Electrodes for all water based applications designed around the customers specific requirements.
http://www.sentek.co.uk

Oxytec A/S
Manufacturer of dissolved oxygen probes, monitoring and control systems for aquaculture. Product information, contacts.
http://www.oxytec.dk/