Either one is fine. My silver TRN has not turned green, but I haven't used it yet. Just to be clear I have a KZ silver upgrade that hasn't turned green because I haven't used it and I have a KZ silver upgrade that has turned green because I have used it. Both KZ cables are eighteen months old. I believe the oxidation process accelerates as the cable is used (as the cable bends oxygen permeates the acrylic coating and the copper wiring reacts).