Castelli Size Chart It's amazing how the right sock can improve your ride. The Geo sock uses a diaphanous mesh around the foot for airflow and a midfoot support strap. The cuff offers just the right amount of compression to make it feel right. Features: - Meryl(R) Skinlife yarns feature bacteriostatic silver ions that resists odor - Pro height - Mesh construction keeps foot cool - Compression cuff