The coldest months of the year also have the least sunlight, so a little extra light keeps us safer on our early morning runs, late-night commutes, and overcast walks with the dog. Smartwool's Reflective Lid features knit-in reflective threads so that headlights shine off our noggin from every angle. In addition to this safety-enhancing tech, merino wool manages our head's heat, moisture, and odor buildup.