▼From the Montbell Official Website This keychain combines a thermometer and a compass, with phosphorescent material used on the surface and the four cardinal directions of the compass. It features an original design with the Montbell logo. The thermometer can measure in Celsius (°C) and Fahrenheit (°F). It can be checked in the dark and also functions as a marker for attached gear. On the back, there is a chart that shows the wind chill based on temperature and wind speed.