From what I understand, the stainless fluxomizers are the same as the clear fluxomizers except that they have a steel casing rather than plastic. I've been told that the clear fluxo's are rev 5s, the only difference from the rev 4s being the amount of wicking material. I took apart an old CE2R4 and the clear fluxo's definitely have more (and thicker) wicking material. I would assume that the stainless ones would be the same.