The Columbia Sportswear Men's Dotswarm Omni-Heat Full Zip Fleece Jacket provides extreme warmth in a lightweight package. Built to keep you perfectly warm during activities in cool weather conditions, this technical full-zip fleece features an Omni-Heat reflective lining that adds cold-fighting power to the MTR fleece's cozy warmth. Zip-closed pockets provide secure storage. Omni-Heat Thermal Reflective - Make Your Own Heat Thermal Comfort. This thermal reflective dot lining regulates your temperature, using space-blanket technology to reflect, trap and retain your body heat, while maintaining a high level of breathability and interior airflow, to disperse moisture and excess heat, keeping you comfortable. Boosts heat retention by 20% on average and the metallic nature neutralizes static buildup.