I took this bottle for school. It is very solid My son is 3.5 years has understood the opening system by rotating the gourd. One good thing, the cap will not close if the bottle is not properly screwed down (so no risk of flight because the child understands that he has not closed) The design is nice and not common The fluorescent cap allows the bottle also find in the dark (useful for children who drink the night) Side washing, can not go into a bottle brush to clean but with hot water and liquid dish wash it very well too. Ultra fast delivery