Nalgene Wide Mouth 32oz Insulated Sleeve

You are a warrior: neither the cold, nor the wind, nor the snow stops you! Except perhaps the lid of your Nalgene which froze solid ... The Insulating sleeve  is an essential accessory for winter sports. Pro Tip: Put your bottle upside down and it will freeze by the bottom rather than by the lid.

Also fantastic in summer: freeze your nalgene in the freezer the day before. With the insulating case, your water will be frozen all day.