This outdoor survival whistle has seven functions.The seven functions are: high decibel whistle, compass, thermometer, retroreflector (which use light reflection to show where you are so rescuers can find you in time), magnifying glass, LED flashlight, seal warehouse (can write your name, address, phone, blood type, etc., in it before going out activities, so rescuers can quickly understand your information).This 7-in-1 whistle is perfect for outdoor sports, camping, outdoor survival, etc.You can also print the company's name or logo on the surface of the product.