what kinda tanks are these

in a recent issue of minitruck, the one with the rusty looking mazda on 22s. there is a section about plumbing your air system. in the main pic there is a set up with 2 clear blue air tanks, 2 az compressors, and manifold valves. my question is, are those actually the air tanks or just for looks. and if so what are they made of. also if anybody has more pics of the set up or the whole truck id like to see it. thanks

they look like the clear hydraulic whammy tanks with custom machined seals on each end.