Having extra carbonating bottles for your SodaStream machine is a great way to keep a variety of drinks for your guests. Specially formulated high-strength PEN withstands both the rigors of carbonation and the intense heat of the dishwasher. A special hermetic sealed cap ensures that you keep the carbonation in so your soda stays fresh and fizzy. Each bottle lasts up to a year and replaces 2000 bottles and cans from store-bought drinks that would otherwise be thrown in a landfill. BPA-free.