Made of high quality materials, strong sealingNote: In 2019, the official classic bottle has been updated with the stopper. What we sell is the new modle, which can be used with the old version before 2019. I am a loyal user of 1.1qt. I have changed the stopper many times in the past ten years. The recommended service life of the water cup stopper is 3 years. Our stopper have been tested to ensure that they will not leak. Because of the version problem, it may need to adapt. If you have a problem, we will actively solve it for you
