Steel coloured radiator pipes, and how to join to them?

[MICH43L]

Hi

I need to add another radiator at the top of my system. I just checked the feed and return pipes are not copper. They are a mucky grey/silver colour (stainless?)

I want to add T-Pieces to these, and some copper pipe off to another radiator. Am I right in thinking these are likely to be stainless, and if so, what's the best type of joint to use?

thanks

 

[thereisawizza]

Brass compression but make sure you have copper olives, not brass

 

[MICH43L]

Thanks.