The Storm®All-Weather Safety Whistle is the loudest whistle on the market. Its patented design allows the Storm whistle to be heard up to fifty feet underwater, due to its unique sounding chamber forcing out all water when the whistle is blown. made in USA.  

Storm All-Weather Safety and  Survival Whistle, loudest industrial and Disaster alarm in the world.  Incredibly loud used by police and survival professionals. Lifeguard approved, Made in the USA. Coast Guard, SOLAS approved