Thanks. I guessed it was fairly standard and similar to lights on boat trailer. Your link led me to this light
https://www.trekwood.com/products/11...-Uni-Light-Red which looks to be what is actually on my TT. Optronics has standard and sealing grommets, but I have been unable to find any source for the sealing grommets, or a complete replacement light with a sealing vs a standard grommet.
I did find some standard grommets at etrailer
https://www.etrailer.com/Accessories...ics/A11GB.html. If they don't appear to seal good enough I will install with some silicone. Silicone appears to be how all the other lights (non Led) are sealed. The new grommets should look better than the torn one.
Thanks