My boat came with a vacu flush system, which I eliminated in favor of macerating electrics. Most of the plumbing is long gone, but I've been holding on to these brackets because they just looked generally useful.

Now I'm trying to clear space in my shop, so they should go live on somebody else's boat. I see that the sealand brackets look identical, and I don't have part numbers... Although quick measurement looks like they're designed to handle tanks or other cylindrical objects approximately 8 in in diameter.

Good solution for that mount round thing to flat surface problem....