The old version of this was labeled as a syn blend. The new bottles do not list the product as a blend. Havoline HM is the synthetic blend formula with seal conditioners added, as well as Maxlife being DuraBlend with conditioners. I'm get the feeling that most HM oils are the respective companies synblend offerings with seal conditioners in them. Makes sense actually, to take a current product and extend it's marketability by pefuming the pig, and giving him a pretty bow.