The Rotronic Hygropalm HP-GTS is a handheld humidity and temperature meter specifically designed to measure equilibrium relative humidity in stacks of paper, cardboard, and textiles. It features a graphical display for trending measured values, programmable visual and audible alarms, and a 64,000-point data memory with adjustable logging intervals from 1 second to 24 hours.

The device uses a Hygromer IN-1 humidity sensor and operates over a temperature range of -10 to 60°C with 0–100% RH measurement capability. Accuracy at 23°C is ±2.0% RH and ±0.3 K. The integrated rechargeable lithium polymer battery (3.7 V, 1000 mAh) provides up to 48 hours of operation with the screen off (logging every 30 seconds) or 10 hours with the screen always on.

Data can be uploaded to a PC via the Micro-USB port, and the HP-GTS is compatible with HW4 software for advanced analysis and configuration. The aluminum probe enables convenient spot measurements, making it ideal for quality control in paper, textile, and storage applications.