The IceFlow water bottle, which uses the same vacuum insulation structure familiar from thermos bottles, is optimized for use with cold drinks: on top of the steel-structured bottle is a drinking spout designed to handle cold beverages. Add a few ice cubes, and your drink stays refreshingly cool for hours. A great choice for hot weather and intense gym sessions! When the spout is flipped to a horizontal position, it seals shut; when flipped upright, its easy to drink from. It can also be detached for cleaning. - Main body material is recycled stainless steel - Double-wall construction with vacuum insulation - The base is narrow enough to fit into most car cup holders - Dishwasher safe If you use the Iceflow Flip Straw bottle with carbonated drinks, do not fill it completely and keep in mind that impacts or shaking (such as when carried in a backpack) will agitate the drink and cause pressure to build up inside the bottle. Open the drinking spout very carefully if you suspec