Fox40 Classic CMG Official Wrist 9608 Properties: FOX40 Classic CMG Official Wrist Whistle. An improved version of the classic Fox 40 whistle. Made of a thermoplastic material with a soft seal (CMG), it provides excellent grip and protects teeth. This model is ideal for those who need to use a whistle for extended periods, thanks to its durability. Thanks to its loudness, the whistle can be heard even over crowd noise, roaring engines, and strong gusts of wind. The sound power is 115 dB.