Advanced science and technology make the Sonik Blast the most efficient whistle in its clase.  Extremely easy to blow, cannot be overblown.  Superior clear loud blast carries over long distances.  Precise whistle chamber calibrations 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 pateneted pealess whistle emits sound power of = 120DB

Fox 40 Sonik Blast CMG