The ultimate cooling shirt. This shirt’s so good at cooling you down when you’re running hard, we’re warning people to not wear them as a base layer. Whereas some shirts just feel cool to the skin, this one actually uses evaporative heat loss to help regulate your core temps. The fabric technology works like a radiator, and is designed to stand just away from your skin to reduce chafing and clinginess when you’re sweating the most. It’s the dream kit for the hottest days.