If, when you press the button normally, the sound is low or no sound is emitted, it means that the gas has been used up and you need to replace it with a new one.
By clicking on the link, you will be leaving the official Royal Philips ("Philips") website. Any links to third-party websites that may appear on this site are provided only for your convenience and in no way represent any affiliation or endorsement of the information provided on those linked websites. Philips makes no representations or warranties of any kind with regard to any third-party websites or the information contained therein.