The World's Thinest Flashlight Keep one of our Lumatec Flashcards little card lights handy to find keys, see maps, or unlock the front door. The flashcard is no ordinary flashlight! Its wafer-thin size make it ideal for active lifestyles and personal security. Dive tested waterproof to 125 feet, the air-tight seal prohibits corrosion and assures years of reliable operation in extreme hot or cold temperatures. Squeeze the FlashCard for bright, dependable light up to 5 seconds a day, every day for two years (45 to 60 minutes total run time).