Survival Signal Mirror Flashes at 0.7, 11.1, 43 mile range

Signal mirror flashes at various ranges from 3“x5“ glass signal mirror with retroreflective mesh aimer, as described at . Modern signal mirrors were developed in WWII for stranded personnel to signal rescue planes/ships for help. Plastic, glass or metal signal mirrors are issued to all US military pilots and US Coast Guard personnel, and are required by international convention in life boats on ocean-going ships and airliners. They are commonly recommended (and sometimes required) in survival kits for hikers and boating. While the very narrow beam reflected by the mirror lets it be seen at long range, as shown here, it also means that they have to be pointed very accurately at the rescuer. US Government testing in WWII established that retroreflective aimers were greatly superior to the other types, and almost all US military issue mirrors since WWII have had retroreflective aimers.