Rubber Bottle Opener is an ideal device for people who are suffering from arthritis, or they have limited hand mobility or strength. It works on knobs and bottles with a diameter of up to 35 mm. When using it, just slide opener over the small knob or bottle top and slowly turn to open, without using too much power or strain to the palm or hand. Once you are done using it, rinse it in warm water and ensure it has dried.