You might not expect something called the UA Extreme Celsius to be lightweight. But we set out to engineer a soft, comfortable 1/4 Zip that keeps you super warm without the bulk. Lightweight UA ColdGear® fabric traps your body's heat, while pulling away moisture that could chill you. And strategically placed lightweight panels add an important extra heat-trapping layer between you and the cold. The comfort of this UA fleece won't surprise you—how warm it keeps you just might.