The eye-catching Sky sports bottle is made of Eastman Tritan?, a material that makes the bottle BPA-free, lightweight, durable, and impact-resistant. The screw-on mechanism ensures that the lid opens and closes smoothly, and it has a built-in handle for easy carrying. The water bottle is single-walled and holds up to 650 ml of beverages. Another handy note is that the Sky fits in the side pocket of most backpacks and most car cup holders. Aluminium, PP Plastic.