Water “flavor enhancers” like MiO can be found in stores all over the place.
They’re pricey, so save those plastic squirt bottles they come in.
They’re the perfect size for toiletries and small enough to get through security.
Of course, this doesn’t have to be a MiO bottle specifically.
Hit the link below for more photos.
Travel-Friendly Liquid Water Enhancers| Travelite