Sonik Blast CMG (Cushioned Mouth Grip)- Advanced science and technology make the Sonik Blast the most efficient whistle in its class. Extremely easy to blow, cannot be overblown. Superior clear loud blast carries over long distances. Precise whistle chamber calibration assures pure frequency performance, less effort, crisper sound. 4 sound producing resonators built into 2 chambers. Won’t freeze, stick or jam – works wet or dry. Flawless patented pealess whistle emits sound power of =120DB.