Ozone Monitors are sold to us from customers who have upgraded, or had only a short-term need for an ozone monitor. We also sell units that were in our rental line. All ozone monitors have been tested, repaired as needed, and come with a fresh calibration certificate along with a warranty.
Our ozone monitors move very fast. If you are looking for something specific please contact our office, we always have units in testing/repair/calibration on the shelf that have not yet made the website.