Capo designed the Thermo Roubaix Skull Cap for the classic 45-55° temperature range. This means it is a fairly low volume hat that fits under your helmet without issue and offers protection in the most popular temperature zone of the offseason. The interior of the hat features Thermo Roubaix hollow core fleece which is warm, cozy and comfortable. The elastic exterior makes for an exacting fit and prevents bunching of material. Simply put, it's a great three season cap. To keep things to a minimum, the cap is designed in one color and one size.