This is the original primary mirror from a Skywatcher Black Diamond 8" f/5 Newtonian.
It has no known issues, but was replaced with an after-market primary for the telescope in question, and is now surplus to requirements.
Would be a good starting point for a home-built scope, as new ones are over $350 from Bintel and others. Note that this is just the mirror, and does not include the mirror cell.
It has been stored carefully, but could do with a clean before fitting in a scope. I'm happy to have a go doing this for you, or can leave it up to you!
$100 + postage, or pickup from Putney 2112.
Contact
John.wheeler.au@gmail.com as well as answering here please.