I was wonder about that, so I Googled a bit and found some info,
https://minglanchem.com/what-are-some-examples-of-viscosity-index-improvers/?srsltid=AfmBOopcdGxMs12nThHgZoM_uqWCPBBBqbdwwJsLN0n26adYcqxNcxfl
which led me to looking up Echo Red Armor's composition, which showed polybutene. So, I...