Its always better to have a whistle that not. The point shouldn't be what whistle between the two or three best and easily available should we carry, but that we should all carry plastic whistles with out a ball inside all the time. I think this list would include the Fox40 that I carry both in the Military (Camo) and at work (Bright Yellow). I whistle takes 10% of the effort a shouting and well over 10x the range.