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-O2-T-METER - Okolab - cell culture
VQM | Handheld CO2/O2 sensor
PureAire Dual O2 CO2 Monitor for Nitrogen or Cryogenics Safety: %, ppm
UNUSED E-INSTRUMENTS BTU900-2P CO CO2 O2 WIRELESS GAS ANALYZER+PRINTER METER | eBay