Rear Main Seal
That's a viton seal. Make DAMN sure when the seal is installed you don't have any more than .010 seal above the block or cap. And that's the MAX. If you have .010 per side, you are putting .020 crush on each end of the seal. You will actual crush the seal out of round.
That's why some guys clock the seal away from the parting line. I don't do that. I fit the seal to the cap and the block seperately. You really only need .005 per side but you may need to practice on a used seal first so you can learn to trim the seal.
Once the block has been lined honed, it adds crush to the seal. And the manufacturers always mentally masturbate over things like crush and don't tell the installer it needs to be checked and corrected.
98% of all rear seal leaks are too much crush.
