I bought the fox 40 classic and the All Weather Storm Safety Whistle. Both are really loud! The fox has a higher pitch. the storm is throatier. if you are not hindered in your breathing both are good choices. If you have breathing issues or are injured such that you can't blow hard, the All Weather Storm Safety Whistle, is so much easier to blow that there is no choice. The Storm is my whistle of choice in my emergency kit.