Merrell Aeroblock provides high wind-resistance and breathability. 90% polyester / 10% elastane. TBD CFM. DWR finish sheds moisture from precipitation. Heathered, double-weave fabric adds sophistication to performance. Water-resistant, zip-secure chest and hand pockets. Reverse coil full zip for smooth and easy on and off. No shoulder seams eliminates friction and pinching under pack straps.