You dont need bulky layers to stay warm The Skea Zumi 1/2 Zip Mid Layer Top provides warmth and comfort at the same time The Zumi Top is light and stretchy so it layers easily It helps you retain body heat while also managing moisture to keep you dry An anti microbial treatment resists odor so you can wear it for multiple days 92pct polyester/18pct spandex Dry Fit fabric Breathable and moisture wicking to keep you dry and warm Lightweight and stretchy for comfortable layering Anti microbial to resist odor buildup Center back measures 25