This sturdy, battery-operated hygrothermograph can record for up to 32 days. Select 1-, 7- or 32-day operation with the flip of a switch. Reads humidity range of 5 to 90% (±3% from 10 to 90% RH). Temperature range is -10 to 50°C (14 to 122°F). Quartz-controlled drive mechanism consistently rotates chart drum even when batteries are weak. Lightweight, corrosion-resistant case for indoor or sheltered outdoor use. A flashing LCD indicates the unit is operational. Included are two C batteries for up to six months of continuous operation-a single button press tests battery condition.