bit of a silly question maybe but I have just got a set of chris king wheels and realised I don’t have the cassette lock ring for the ISO rear hub, I don’t have my old wheels to try but the question is do I need the chris king specific shimano casstte lock ring or is it just a generic item?

You don’t need the CK lockring.

Any old one will do; SRAM, Shimano whatever.

Extra bling points for the King one, though!

You use the lock-ring that came with the cassette…the CK ones don’t come with the hubs and are extra dollar.
Beaten by seconds! 😀 I must be poor. I’ve the CK alloy one, I couldn’t justify the Ti one. 😐

great stuff thanks all for the swift responses much appreciated.