Coghlan's Four Function Whistle is a useful and simple multipurpose tool when adventuring outside. Combining the essentials for navigation and signaling, this compact tool is handy to bring along wherever you go. The Four Function Whistle includes a thermometer, magnifier, compass, and whistle. With this tool, you can alert others of your presence thanks to the loud whistle. Looking to find your way? Use the compass and the magnifier to read maps and orient yourself. The handy thermometer provides accurate readings in Celcius and Fahrenheit.