Founded in 1991, Pace Scientific develops and manufactures data loggers and sensors. Our four channel XR440 Pocket Logger® works with over 40 direct connect sensors, including Temperature, Humidity, High Pressure, Lo......Founded in 1991, Pace Scientific develops and manufactures data loggers and sensors. Our four channel XR440 Pocket Logger® works with over 40 direct connect sensors, including Temperature, Humidity, High Pressure, Low Pressure, AC Current, DC Current, AC Voltage, Power, Light, Solar Radiation, Soil Moisture, with no external power!