Designed for precision, this mechanical hygrometer automatically adjusts to provide accurate humidity readings. Its compact and round design makes it suitable for use in cigar humidors, guitar cases, and other storage boxes. The luminous feature ensures visibility at all times, helping you maintain the ideal environment for your cigars. Features -Color:Golden -Material:Metal -Size:3.70X3.70X1.00cm/1.45X1.45X0.39in -Dial diameter: 37mm -Back diameter: 32mm -Thickness: 9.7mm -Measurement error: +/-5%RH (between 40~70%RH) -Automatic humidity detection: automatically detects humidity levels, no batteries required -Glow in dark: luminous design makes it easy to read in dark environments, enhancing usability -Accurate humidity measurement: ensures precise monitoring of cigar humidity, maintaining their condition -Dual compatibility: works with both cigar humidors and guitar cases, versatile usage options -Lightweight and portable: compact and lightweight design makes it easy to carry and store, ideal for travel Package list: 2 x cigar humidity meter