Montane Ultraflask - 500ml Soft compactable hydration flask with wide opening and 3D base. The Montane UltraFlask™ 500ml by Hydrapak® is a compactable flask for quick, easy hydration when on the move. The flask compresses for easy storage and prevents water from sloshing. The new wider top opening allows for quick and easy filling / cleaning whilst the high performance soft silicone bite valve provides a high flow rate. Features: Soft, flexible TPU flask body 3D base Wide screw top opening High flow rate soft silicone bite valve Dishwasher safe (top rack) BPA free / PVC free / meets or exceeds FDA and EU regulations Compatible with Softflask Long Straw and Softflask Short Straw Liquid capacity: 500ml  /  16.9oz