Industrial Air Quality Meter with Real-Time Data Recording of CO2, CO, O2, Temperature & Humidity,(6 in 1) by Lutron AQ-9901SD(Handheld Indoor Detector Sensor Meter Monitor Device Measurement): Amazon.com: Industrial & Scientific
CO₂, oxygen, and TPO meter :: Anton-Paar.com
Haffmans CO2/Dissolved Oxygen DO Combined Meter (c-DGM) - Murphy and Son
Amazon.com: Hydrofarm APCEM2 Autopilot Desktop CO2 Monitor & Data, Data Logger, White/Blue : Industrial & Scientific