Reifflex cellular padding was a material used in the armor of Darth Vader. It was also implemented in the base of helmets utilized by the Imperial Stormtroopers by the time of the Battle of Endor at the earliest, as well as the interior of the standard-issue flight helmets for X-wing pilots in the Alliance to Restore the Republic since at least the Battle of Yavin in 0 BBY/0 ABY.