The flip cap provides a narrow mouth spout for on the go drinking the medical grade silicone flip top seals with the polypropylene pp5 cap the pivoting handle provides a great way to carry the bottle and stows out of the way while drinking wide mouth access makes it easy to add ice cubes or fresh fruit slim and mobile the 475ml travels wells and looks great doing it the silicone flip top seals when plugged but is not upside down bottom of the bag leakproof