We developed HEATTECH in response to customers’ demands for functional innerwear to complement UNIQLO’s previous lineup of mostly cotton innerwear. Our debut HEATTECH product line was launched in the fall/winter 2004 as warm innerwear for men, combining the merits of heat-retention and anti-perspiration functions. The following year we began selling similar products for women. By combining our original HEATTECH fibers with a special milk protein, we were able to create a fabric that is smooth, soft and comfortable. The products proved so popular in the 2007 fall/winter season that production was nearly outpaced by demand.