This is plug for the NSX rear garnish to help prevent water from entering the engine compartment and soaking the rear bank coils.

Version 1 is designed to use some kind of weather seal around the outside to make a watertight seal. Using a foam weatherstrip makes it easier to install.

Version 2 uses an o-ring for the seal. This slightly more difficult to use to get a good seal. Scaling will be required.

Depending on the material used to print, some scaling maybe required in order to get the right fit.