The Guardian is constructed from high-quality ASA plastic with low thermal conductivity and a gloss white finish in selective areas to lower emissivity with an IP rating of IP53. The Guardian is filled with foam to provide additional thermal insulation. Additionally, a quantum sensor is mounted on the top of the shield to measure PAR (SM-500
) or ePAR (SM-600
). The internal airway utilizes a small venturi constriction to maximize airflow efficiency over the thermistor, which minimizes the thermal boundary layer’s influence on temperature measurements. Simultaneously, a separate module used to measure CO2
, humidity, and pressure is aspirated by a passive, low velocity airstream using a “fluid entrainment” principle.