A compact emergency air horn for signalling over distance.

A whistle needs lungs. An air horn does not — which matters if you are injured, exhausted, cold, or at an altitude where you have nothing to spare. Press the button and it does the work.

Carries further than a whistle and cuts through wind and running water better. Three blasts, repeated, is the distress signal.

It is also the fastest way to get a group's attention across a campsite without shouting.