Crane does not supply Isky with ductile rockers. Since "CRANE" is embossed in the bottom of the casting, that would be a bit tough for Isky to explain. Crane went to all new dies and tooling for the ductile rockers over four years ago, strengthening critical areas, and improving overall quality. Also, the pre-2009 rockers had a flame hardened tip, while all the newer ones have an induction hardened tip for better hardness and consistency. Both 1.5:1 and 1.6:1 ratios are available. Regards, Chase