Our Ailia Bottle is made up of a 6-layer explosion proof material. The Ailia green external material that we all love is made of Flannelette. Flannelette is often made from cotton or a cotton blend. It's soft, cozy feel makes it the perfect fabric to keep you warm, comfortable and for long lasting heat. Overall, flannelette is a comfortable and versatile fabric that is well-suited for bedding and sleepwear, providing warmth and a soft touch.