The base fabric is castelli39s tried and tested 39warmer39 brushed fleece fabric that will keep you warm and dry at the front castelli have overlayed the base with their new voile whisper fabric for nearly weightless wind protection while allowing a high degree of permeability the double layer front provides unprecedented ventilation and moisture management warmer warmer more than just the name it is exactly what this fabric delivers during workouts its fleecy inside keeps you wa