The clear Sky colour-pop water bottle is made of Eastman Tritan, making this bottle BPA-free, light, durable and impact-resistant. The bottle is single-walled and holds 650 ml of liquid, and it fits in the side pocket of most backpacks, as well as in most car cup holders. The twist-on lid ensures easy opening and closing, and has a built-in carrying handle. Eastman Tritan.