Sometimes it's not quite cold enough for a skull cap under you helmet, but you still need something to keep your head warm. The Castelli Viva Donna Headband is designed specifically for the female rider who needs to stave off Jack Frost from biting at here ears. Castelli constructed the headband from its Thermoflex fabric. This material features a polished polyester finish on the outside and a lightly brushed soft fleece on the inside. Essentially, the soft interior traps warm air against the head, while the breathable outside allows moisture to escape and evaporate. This way, you're able to stay dry without running the risk of overheating. Additionally, the fabric was also left raw at the edges, meaning that it won't bunch under your helmet. However, you're probably wondering what makes this headband women's specific' Well, it features a small trapdoor in the back to accommodate a ponytail. It's a small detail, but it adds up to a big deal when you have long tresses. The Castelli Viva Donna Headband is available in the color Black and in one size.