Nothing lasts forever, but this almost-forever amber safety light will flash until the 6V lantern battery you provide for it dies. Made by safety-conscious Brits, it flashes a tad faster than once a second and measures 8-1/4" tall on a 2-7/8" square base. Has a 3" dia fold-up loop on one side, plus a small, 3/8" wide cord-loop and a 1/4"-16 mounting nut. Might have a touch of British schmutz on it, but it's plastic so wash it off. Nice trunk item for accidents/breakdowns.