The Aonijie Soft Flask 450ml is a convenient, foldable soft flask with a bite valve and an antibacterial finish. The flask compresses as you drink to eliminate water sloshing around inside it. The updated soft bite valve has a higher flow rate, making it easy on the teeth. It is both slim and lightweight and will fill easily thanks to a wide mouth opening. It is also hydration vest compatible and will fit easily in most hydration vests, belts or pack pockets. The soft material conforms to any pocket for comfortable carrying.