The Siena Roubaix Knickers are named after the Thermo Roubaix fabric used in their construction. Thermo Roubaix is made up of hollow core fibers, which effectively maximizes the surface area of the material. This increases the material's wicking properties and creates countless micro pockets of trapped air to act as insulation -- basically the same principle that makes Merino wool such a quality insulator. The benefits of Thermo Roubaix are also evident in the Sienna Roubaix Tights' elasticity and abrasion resistance. The Veloce HD EIT Insert is provided by Elastic Interface, a division of chamois giant CyTech. This women-specific chamois is channeled for maximum airflow, boasts antibacterial properties, and is designed to stretch and move with you whether you're hammering through cold-weather intervals or spinning out base miles. The abbreviated fit of the knickers also recommends them for short, hard efforts in cool weather -- like a 'cross race -- or in conditions where you want some extra insulation but full-length tights would be overdoing it.