It seals in warmth. The 7-gauge, two-ply knit from the Recycled Cashmere Crewneck did a great position of retaining body warmth when we wore it on what passes for a cold autumn early morning in Southern California; https://haimavbqw852620.evawiki.com/8842761/the_smart_trick_of_winter_wardrobe_that_nobody_is_discussing