Your best chance for survival is being rescued in a timely manner. Your Rescue Laser Flare will attract attention to your position for up to 20 miles away! Has extreme range for signalling, is waterproof to 80 feet, nonflammable and nonhazardous, has 40 hours of continuous use and has one easily replaceable alkaline CR123 battery. Designed for the maritime environment. Signal duration is equal to 2,400 one-minute pyrotechnic flares.