AC Infinity - VPD ThermometerAC Infinity VPD Thermometer A highly innovative laser thermometer gun designed to instantly measure leaf VPD, air VPD, ambient temperature, leaf temperature, and relative humidity to precisely calculate true VPD data. Using these environmental figures, you can calibrate your smart controller so it can accurately detect the climate and trigger your grow devices at precise times. This is the first of its kind to track the VPD (vapor pressure deficit) of