The Ozzo thermos is sturdy and has a practical hidden straw. It fits perfectly in a children's backpack. Comes with two whistles.
The thermos flask with a whistle is made of 18/8 steel, which is a very high-quality steel. This makes the bottle very durable and long-lasting. There are no coatings on the inside of the bottle, and no flavors or chemicals of any kind come off.