Western Mountaineering Storage Sack Extra Large. This allows the down to breathe and stay lofty. When possible your sleeping bag should always be stored in this larger bag. This is an important way to protect your investment and to prolong the life of your sleeping bag. Specifications for Western Mountaineering Storage Sack XL: Manufacturer: Western Mountaineering Size: Extra Large Fabric/Material: Synthetic Quantity: 1 Lining Material: Synthetic Application: Camping Western MountaineeringSTORAGES: Storage Sack Extra Large