General Tools DTH3007SD Data Logging Thermo-Hygrometer with Excel Formatted SD Card Four-function instrument measures temperature/humidity, dew point, wet-bulb temperature and surface temperature Features auto power off function that can be disabled for data logging and calibration Automatically logs measurements at sampling time settable from 1 second to 1 hr.; supports manual data logging and changing of SD card storage location Big (2.5 inch diagonal) front-panel green backlit LCD is easy to read; displays maximum and minimum readings and holds any reading Field calibratable humidity measurement