The Fox 40 EcoBlast — a loud air horn powered by a refillable air chamber and a hand pump, rather than a compressed gas cartridge.

Disposable gas horns run out, and they run out silently — you find out when you need it. This one refills with the pump in about twenty strokes, so it never reaches zero permanently.

No propellant means it is legal to fly with, legal to ship ordinary ground, and safe to leave in a hot vehicle. A pressurised gas canister in a truck in a Central Valley July is a thing worth not having.

Far louder than a whistle and it needs no breath at all, which is the point if you are injured, exhausted or at altitude.

Used on the water, on trails, at trailheads and on job sites. Three blasts, repeated, is the recognised distress signal. One blast means I am here.