Hi DocI,
The replacement sink baffle or mounting gasket for a Badger 900 is the standard mounting gasket included in the InSinkErator Mounting Gasket Kit (MGK-00).
The Mounting Gasket Kit includes one standard and one deluxe mounting gasket. These gaskets are properly labeled. To ensure proper installation, please make sure to use the appropriate gasket for your disposer. I have included links below for your reference. Also, please be reminded that the disposer should be uninstalled when replacing its mounting gasket.
InSinkErator Mounting Gasket Kit:
http://shop.insinkerator.com/p/insi... InSinkErator accessories may be purchased through most home improvement centers, plumbing supply houses and online stores.
If you have questions, please do not hesitate to contact us through insinkeratorfeedback@emerson.com or call InSinkErator AnswerLine at 1 (800) 558-5700.
Sincerely,
Jerica
InSinkErator® Customer Service