Description:optional UV-coated, color-corrected flashtube for Ultra Series Flash Units that were purchased after January 1991 (user replaceable, arriving with instructions for use) as the Ultra Series requires two half-circle flashtubes, you may purchase a single UFT2UV tube, or purchase the pair (it is recommended that both tubes be replaced at the same time, for best results) typical life expectancy between 250,000 - 500,000 flashes UFT2-B White Lightning Flashtube