Bests & Worsts Reviews from Amazon

I teach skydiving, and while Hollywood would have you believe that entire conversations can easily be held while in freefall, this just isn't the case- 150mph winds tend to be quite loud. Just for fun, I began buying every "miracle whistle" I came across, and testing them in freefall with friends, thinking that we could use a simple code for a few things, just to give us a line of communication without requiring line of sight. I had tried everything- fox 40, storm, etc. I hadn't tried the Hyperwhistle yet because it looked too large and ungainly. Finally I was out of alternatives so I ordered one. OK...this thing is loud. Crazy loud. Any reviewer who claims otherwise or compares its volume unfavorably to any other whistle on Amazon as of the date of this writing is lying. No doubt about it. In fact, simply angle the mouthpiece into the relative wind during freefall and I think they can probably hear it on the ISS. LOUD. Seriously. Will it ever become a standard part of a skydiver's kit? I don't know...it's still very loud up there, while it can be heard, it doesn't have the volume to get your attention unless you're specifically listening for it. Now, once you're under canopy, you can hear each other a looong ways away- certainly further than 2 miles!