Columbia Sportswear has introduced what it claims is the industry’s first external thermal shield against cold weather. The exterior of each jacket in its new Omni-Heat Black Dot collection is covered by thousands of dots made of aluminum and coated in black. These dots collect heat from scattered sunlight, and presumably channel it to the jackets’ Omni-Heat 3D thermal-reflective lining, a feature introduced a decade ago. According to Columbia, laboratory and field tests show that jackets equipped with the system retain heat “longer than jackets without this new technology.” The three models in the collection, each in men’s and women’s versions, are on sale at www.columbia.com/tech-reflective/ and at selected retailers. The Dawn Watch Black Dot Jacket retails at $350, the Barrett Spur Black Dot Parka for $600 and the Three Forks Black Dot Jacket for $280.