The ACME No. 649 Survival Whistle helps you to attract attention if you get into difficulty. This life saving rescue whistle is made from tough, shatterproof plastic with an attention grabbing and loud discordant note. The world's first life saving whistle developed in 1949. Offers great ease of blowing giving lots of sound for almost no effort - important if you are young, elderly, injured or cold. Dual frequency designed to stand out from background noise Important in survival situations. This whistle works in water and will not adhere to the skin in sub-zero temperatures. S.O.L.A.S approved. British Admiralty and NATO approved.