Should have listened to other reviewers
Cap for the mouthpiece is really frustrating to work with, I thought some of the other reviewers might have been too finicky but no. It's unreasonable to have to use so much force to open and close it. My protein shake splashes out when I manage to open the cap, it takes that much force. Closing takes just as much effort, except sometimes it feels like it closed but actually didn't so the contents dribble out.
amazon reviews