Synergistic Research actually used to claim their SR-20 fuses were not directional since they were subjected to the Telsa treatment in both directions, which supposedly made them non directional. That is according to a Norm Lutweg review in Stereo Times. Dunno what SR claims in terms of directionality for Red and Black fuses. But to the point, if SR didn’t believe their SR-20 fuses were directional they wouldn’t have paid any attention to the writing or symbols on the fuse, yes? Therefore, the writing or symbols on that particular fuse, at a minimum, is most likely random with respect to directionality.