Vernier does not sell holders or storage racks for our oxygen gas sensors. But the shaft of both the Go Direct O2 Gas Sensor and the O2 Gas Sensor can be placed in 50 mL conical tubes, which can also be called a 50 mL centrifuge tube. This means that holders or storage racks for 50 mL conical / centrifuge tubes can be used to hold our oxygen gas sensors. You should be able to find a variety of these racks from different suppliers. They will all vary in price, but we have found some very affordable racks on Amazon. Below is an example of a rack we found that is sold with a series of 50 mL “childrens test tubes” which were reallly just 50 mL conical tubes. You can see that the holder can be used for our oxygen gas sensors and even a variety of other sensors. We would recommend a rack / holder that is a bit taller, but this rack was very affordable. For long term storage, we recommend wrapping the end of the oxygen gas sensors in a plastic bag, as this will limit exposure to oxygen gas when not in use.