Perfect Seal: Includes rubber gasket pre-installed in base for complete seal with cup.
Important Tips: Note1: The rubber gasket in bottom blade maybe loosened during transportation. Before using the bottom blade, please check the rubber gasket and be sure it is put snugly into the replacement bottom blade.Note2: Please TAKE OFF the PRE-INSTALLED GASKET in the bottom blade, if you're going to use this replacement gasket.