This is the new model of the Fizz Keeper and is a lot   better.  It works much the same way as the old one but a big advantage of this Fizz Keeper is that you don't unscrew the cap everytime you want to pour;  the top conveniently pops open while the cap stays on.  Just snap it closed, squeeze the Pump & Pour several times until plastic bottle becomes firm and keep the fizz in.   When you want to drink just flip the top open and pour.  Fits all bottles up to 2 liters.

CSS 027 Fizz Keeper Pump & Pour...........$ 4.00