Features:1 ， whistles ( nuclear design ， greatly increasing the loudness of the whistle ， nylon lanyard )2 ， refers to the North ( South ) pin ( accurate， clear )3 ， hygrometer ( ambient temperature a pretty good idea )This little whistle also has a compass， thermometer function， another with a lanyard for easy carry. In the wild ， when these are very necessary tool that can provide timely helpThis product is suitable for tourism ， meetings ， outdoor activities and various competitions events.