The Extech RH520A-220 is a versatile environmental data logger designed to record and display humidity and temperature simultaneously. Featuring a large dual graphical LCD with adjustable resolution, it provides both numerical and graphical readings, along with time and date stamps. It measures relative humidity from 10% to 95% RH and temperature from -20.0°F to 140.0°F, calculating dew point, wet bulb, and GPP through LabVIEW™-based software. The device has an internal memory for up to 49,000 data points, easily transferable via RS-232, and supports wall or desk mounting with alarms and remote probe options for comprehensive environmental monitoring.