Fox 40 Classic CMG Whistle 115 Decibels of high pitch Shrill rises above ambient Noise-can be heard up to a Mile away 100% constructed of high-impact ABS plastic-So they're 100% impervious to Moisture Peals Design, No moving Parts-nothing to obstruct Sound, nothing to jam, break or freeze CMG made of thermoplastic is preferred by officials who hold the whistle in their mouth to assure a secure grip Fox 40 cannot be overblown-the harder you blow, the louder the sound