A camping whistle can be used to alert people if you are in distress and should be carried when hill walking and mountaineering. If you do find yourself in trouble then the internationally recognised distress signal is 6 blasts of the whistle with a 1 minute break and then repeated. The reply is 3 blasts with the same pause. When you hear a reply whistle, do not stop, as the rescuer will be using it as a directional locator. For extreme cold weather, do not take along a metal whistle as it may freeze to your lips.