Approved for use in all Outboard Engines; previously only our synthetic blend could make this claim. For use in all 4-Stroke Marine Engines - New formula 4-Stroke oils are approved for use in certain marine 4-Stroke Outboard applications and exceeds all Marine industry 4-Stroke oil requirements including FC-W and FC-W Catalyst Compatible. In addition, all 10W30 and 25W40 oils are now fully FC-W Catalyst Compatible