- Accurate Measurement Comparison: The contrast pen on the lens allows for easy comparison of measurement values, helping you determine if atmospheric pressure is increasing or decreasing over time. - High-Quality Sensor Technology: Equipped with a hair spring temperature sensor and a wet hair spring, this device features a robust gear structure and a reliable barometer movement, ensuring precise readings with a 1-second clock mechanism. - Comprehensive Measurement Range: - Temperature: -30 to 50 °C, with an accuracy of +/- 2 °C. - Hygrometer: 0 to 100% RH, with an accuracy of +/- 5% RH (optimal range 40 to 70% RH). - Barometer: 950 to 1070 hPa, with an accuracy of +/- 5 hPa (optimal range 980 to 1040 hPa). - Constructed from durable brass housing, a sturdy base, and an acrylic lens. - Versatile Applications: Ideal for use in a variety of settings, including ships, factories, laboratories, and homes. - Compact and User-Friendly: Designed for ease of use and portability, making it an essential tool for anyone needing reliable environmental data. This product is sold in sets of four, ensuring you have everything you need for multiple locations or applications.