Women’s Adidas climawarm long sleeve top with zipper diagonal at neck line. Zipper is pretty much invisible when zipped up and is like a mock turtleneck to keep you warm in the cold. Medium weight. Can be unzipped as you warm up. The zipper is a little tough at the collar but it has been that way since I bought it new (works fine I think it’s just the thickness of the collar at that point.) Older style too but is great in colder temps as a layer. I just need to clean out my closet.