The bottles have 16 fl. oz. capacity and come with special hermetic sealing caps, that keep the drinks fresher and fizzier for a long time. The bottles are BPA free and can be used for up to 2 years. Each SodaStream carbonating bottle replaces over 2500 bottles and cans from store-bought drinks. 1/2 Liter Carbonating Bottles Features: Carbonating Bottles, 16 fl. oz. Capacity, Hermetic Sealing Caps - Keep Drinks Fresher & Fizzier for a Long Time, Can be Used for Up To 2 Years, BPA Free, Replaces Over 2500 Bottles & Cans From Store-bought Drinks"