A State of the art motorcycle engine oil. Golden Spectro 4 uses a sophisticated blend of complex synthetics to produce a lubricant that stays in grade under all riding conditions. Specifically formulated for high rpm motorcycle engines where extreme cam profiles and high horsepower are the standard. Special proprietary polymers enhance shifting in common sump engines. This is the oil you've heard about that improves shifting and gets rid of the clunks. Golden Spectro 4 sets the standard for synthetic blend motorcycle oils. Exceeds all known motorcycle manufacturer's warranty requirements API SL/JASO