Million Magnets Upgraded Toothbrush Waterproof Shaft Rubber Seal, Generic Replacement Parts for All Models, Smart and Brushsync Compatible or Regular HX751x HX681x HX9690 HX9957 HX683x HX992x HX993x

The regular rubber seal is required for HX9120, and is available from Amazon at While some customers prefer the rubber seal found in item B07J514P75, when some customers prefer to upgrade and improve the sealing of their toothbrush, we also recommend this upgraded rubber seal available at Amazon The Rubber Seal 03B08QZ61ZG1 should fit most models. A list of compatible models can be found on the second picture. (Hint we listed one of the types of metal shaft that won't fit in the tip. even if there are more models, it should still work for them. For installation instructions, please refer to the video on the product page if you need the advice. If you have any other questions about the product, please contact us. I send my best wishes to Camille and the Customer Service Team, Camille