A whistle has long been considered as the primary way to signal others in a time of need. If your life depends on a loud easy to hear signal, many whistles just don't get the job done. Peter Kummerfeldt, owner of the Survival Consultant Group, has this to say about Cameron's LIFE SAVER #1 SIGNAL WHISTLE. "When compared with other whistles the LIFESAVER #1 is more durable, louder and easier to use than any other that I have tested. The LIFESAVER #1 whistle has been and will continue to be prominently featured in all of my outdoor safety seminars." Last year when I was filming for Peter Kummerfeldt he blew a vast selection of whistles. The LIFESAVER #1 was definitely the loudest(up to a claimed 118 db) and clearest. So why do you need whistle? A whistle is great anytime that you need to attract attention. Your friend can't find you, or maybe rescueers are so close yet can't see you. If people wore one in high crime areas, I believe assualts could be greatly reduced. Buy one for your children and wife and it isn't a bad idea for men and boys to have one either in areas of high crime. Whistles have snaps which makes them easy to attach to zipper. I have one on every pack that I carry.