Extech RHT20 humidity and temperature datalogger. Records up to 16,000 humidity + 16,000 temperature readings, USB download. Range: 0-100 % RH ±3 %, -40 to +70 °C ±1 °C. IP67 rated for wet environments. Applications: cold-chain shipping monitoring, warehouse condition tracking, food/pharma cold storage verification, cargo insurance temperature-excursion evidence. Data-download software (Windows/Mac) included. Battery-powered CR2032; typical 12-month deployment.