Patagonia has mastered the layering system, and the Patagonia Thermal Weight Zip-Neck Top has a hardly noticeable weight-gain for the added features and durability it provides. A backed front-zip is comfortable against your skin and opens quickly for ventilation without sacrificing core warmth. True to Patagonia’s leadership in sustainability, the Patagonia Thermal Weight Zip-Neck Top is constructed from recycled and bluesign approved fabric.