It's just wat it is, the Roman armour-to-go for your avarage battle against the Germans... made of 1mm. mild steel, handmade brass fittings & rivetted leather.
A while ago I made this armour for a soldier. It's 1,5 mild stee and leather. Patina was done with heat & oil, and I burned it to a nice, crisp layer. Also rust proof by the way...