Whistles by Fox 40. Details:Fox 40 Sonik Blast CMG whistles are extremely easy to blow. Advanced science and technology makes this the most efficient, loudest whistle ever produced by Fox 40. This whistle cannot be overblown and emits sound power that exceeds 120 decibels. This clear loud blast carries above the loudest crowds and noise, and over extreme long distances. The CMG stands for cushioned mouth grip. This whistle is ideal for those who need to hold the whistle in their mouth for extended periods of time. Ideal for large crowd arenas, airport runways, search and rescue, outdoor activities and any situation where a loud signalling device is needed.