Sea Dog&';s Duotone whistle is a unique survival whistle that clips to your pocket or belt. It has an extremely high decibel Level creating a wide range in which to be heard with very minimal effort. The design of High Impact Polypropylene means no moving parts. Thus ensuring the user a jam or freeze free use in the time of an emergency. Has no moving parts or balls that can jam or corrode Meets USCG requirements for use on PFDs Handy clip secures whistle until needed