ecoTech develops and manufactures a variety of environmental monitoring equipment, including redox electrodes `https://www.ecotech.de/`.
ELANA offers custom made redox electrodes and environmental consulting `http://www.elbtalanalyse.de/index.html`.
SWAP offers multiple redox electrodes with over 25 years of experience `https://www.swapinstruments.com/about-us/`.