About this product
This is a handheld air horn worked by a hand pump rather than a compressed gas cartridge. You squeeze the bellows and the air drives a reed. That one design decision makes it a fundamentally different object from the aerosol horns sold beside it.
A gas horn has a finite number of blasts in it, and there is no way to tell how many remain. It is always empty when it is needed, and the refill cartridges are rarely available locally. A pump horn has no such state. It can sit in a boat locker through two rainy seasons and work the moment you pick it up, and there is nothing that can leak, expire, or be bought again at a price.
For boats, a sound signal is a basic piece of safety equipment. It is how you signal a manoeuvre, warn another vessel, attract attention in poor visibility, and call for help. A whistle is the minimum and carries a certain distance; a horn carries a great deal further and does not depend on how much breath you have left.
Away from the water it is the same simple thing: starting races and matches, marshalling events, getting attention across a site, warning off animals near a camp. It weighs almost nothing and works in the rain.
Keep it rinsed if it lives on a boat – salt is what eventually stiffens a bellows – and blow it occasionally rather than never, so you know it works.
Marine Pump Air Horn - Hand-Powered, No Gas Canister or Batteries