This outdoor survival whistle has seven functions. Whistle: 3000 Hz high decibel, easy to catch attention. Compass: Good helper to distinguish direction. Thermometer: Grasp the temperature of current ambient. White LED Flashlight: An emergency lighting in the dark (A 3V button battery included). Magnifier: Using to make a fire. Mirror: Utilizing the principle of sunlight reflection, help search and rescue personnel to determine your position. Storage: Store personal information; let your situation to be grasped in the first time.