I get tired of yelling to get people's attention, it's not always effective. This whistle is perfect. it's sharp tone is unmistakeable and provided a directionally perceivable alert. Most times when I yell people just look side to side instead of up at the Paraglider landing while they stand in the designated landing areas, all they can tell is somebody has yelled. But when I use the whistle, a few short chirps and immediately they look right at me.
Feedback:
I would ditch the clip and replace it with a small hole for a lanyard on the end.