This deluxe 3-pc set of approx. 2-3/4", weather instruments includes barometer, thermometer, hydrometer with gold dials and bezels with plastic collars for inserting into a 2-1/2" opening by 3/4" deep. The barometer is used to measure the changes of temperature humidity and atmospheric pressure parameters with setting needle to note changes. Measurement range: 960?1060hPa, -20?50C, 0?100%RHis. The thermometer is used to measure temperature. It detects changes in physical properties of an object or substance as the temperature of the object changes. 0.5F (0.3C) . The hydrometer is used to measure density or relative density of liquids based on the concept of buoyancy. They are typically calibrated and graduated with one or more scales such as specific gravity. The photos of finished weather stations are not included. Shown only for displaying purposes. Questions, please message us.