Storm Safety Whistles Blown and heard on land, up to 1/2 mile, and even underwater, up to 50 ft. A non-corroding thermoplastic housing is easy to grasp, and the double chamber design allows it to be blown when held right side up or upside down. Both whistles are used by Police Departments, the U.S. Military, U.S. Coastguard, and Emergency and Diving Operations who appreciate their all-weather use: each whistle purges moisture yet still delivers a loud, penetrating sound easily heard in any environment. Loud sound for hunting, diving, hiking and adventure Sports. Made in USA. World's Loudest Referee Whistle! SE- (B Black, O Orange, Y Yellow) MPWLO Safety Orange w/19" Lanyard Blister Card