This Western digital humidor gauge accurately measures and displays relative humidity and temperature to assure your cigars are stored in the ideal conditions keeping them in prime smoking condition. The Caliber III never requires calibration; there are no springs to stretch or moving parts to wear out. Features easy to read large display, slim profile design, and magnetic mount. Accuracy +/- 1% humidity, +/-1 degree temperature. Full 5 years guarantee. Dimensions: 3.5" x 1.25" x .25".