I agree with ParamountScapin. I found a little more detail on the Scapin corrosion protection process. The process is not verified, but it sounds correct: "All of their frames are internally varnished, observing strict criteria in the safeguard of the environment. The first in the world to introduce a special anti-corrosion treatment called A.W.P., a protective treatment whose aim is to make the steel frames resistant with time to corrosion and to rust, externally and internally. A.W.P. (All Weather Proof) is in reality a triple process composed of zinc-nickel plating, phosphoric treatment and finally of a "black electrophoresis"."