there are two: professional and exclusive. I think it's £20 the difference. The new exclusive regulator (whos's design I don't actually like) has a complete plastic mould all around it, this would make it impossible to take it apart and service it yourself (not that you would, and I've been through a few regulators as well), it costs about £100 but I'll be buying it for the needle valve that Dennerle claim is very accurate. The other regulator has the needle valve all metal, and considerable improvement on the previous one I must say. I'll be buying the spare needle valve for this regulator to test out, but all this in good time . . .