I recently received a grant for the Ohio STEM Learning Network & Battelle to purchase carbon dioxide and oxygen sensors from Vernier Science Education. O₂ sensors have to be stored upright, so I designed this holder to store them in my cabinets. The idea came from similar pH sensor holders that I had printed from a Thinigverse model by NAbel. This was designed on Tinkercad and I also printed one for the CO₂ sensors even though they don't have to be stored upright.