Exactly. I do happen to use Serfas lights. My headlamp, a TSL-S250, has a blinky mode, which I always have on in daylight. The taillight has a smaller battery and so is slightly less satisfactory. I haven't run that blinky down on it's lowest setting, but I'm guessing it will only last about 5 hours. So I always have a second, battery blinky just in case - a Turbo Superflash. I'm jonesing for a DiNotte tail light.