On The Fly Starter Kit includes a large bottle sock to be utilized with wide bottles from 8 to 11 oz. and five large individually wrapped disposable bottle warmers. Each warmer provides up to eight hours continuous heat. The bottle sock is made with all natural ingredients: 95% cotton and 5% spandex. It's washable in cold water. The warmer packs are made of iron powder, water, activated carbon, wood, powder and salt. The heat is air activated when the warmer is removed from its packaging. Bottle is not included. Extra packs are available separately. Launch date: 2009.