Pearl Izumi's Thermal Zip-Neck Long Sleeve Baselayer is a winter-weight top made to keep you warm and dry. It's made from their P.R.O. Thermal Fleece fabric with Minerale yarn that dries significantly faster than standard polyester. It boasts superior breathability and feels great next to your skin, and the eight-inch zipper allows you to dial in venting. You'll love the great fit that's perfect under form-fit tops, the long back that accommodates your riding position, and the UPF 30+ rating.