copper lines with accuair setup ??

[67cheby]

i have seen a couple different pics of copper lines running into what looks like the factory plastic airline inserts on the accuair valve setup ? am i seeing this right or is there special fittings on the copper to replace the plastic air line fittings ?? my thoughts is i want the look of the hardlines with of course the least amount of money , so i was thinking run the copper tubing and paint it black or charcoal grey ? any input anyone ??