AC Infinity VPD ThermometerAC Infinity VPD Thermometer Precision Climate Monitoring for Grow Rooms The AC Infinity VPD Thermometer is a precision tool for monitoring temperature, humidity, and vapor pressure deficit (VPD) a critical factor in plant growth and health. By tracking VPD, growers can optimize transpiration rates, nutrient uptake, and overall plant performance. Designed for indoor gardening, hydroponics, and greenhouse use, it features an easy to read digital display