Signaling for Help: Mirrors, Whistles & PLBs (4-oz Guide)
Compare survival signaling methods: signal mirrors, 650-2000 Hz whistles, and 4-oz GPS Personal Locator Beacons. See which works day, night, or in bad weather.

Compare survival signaling methods: signal mirrors, 650-2000 Hz whistles, and 4-oz GPS Personal Locator Beacons. See which works day, night, or in bad weather.