Mannesmann of Germany operated a steel processing plant in Dalmine, east of Milan, and it is said that post WW2 the Mazzuccato family purchased it and that became ORIA.
Mannesmann supplied the steel, then ORIA completed the transition into bicycle tubing.

Nice ORIA article on the Italian Cycling Journal HERE

Interesting special model: Oria Special TC 0.8 tubes: CroMo tubing with additional reinforcing ridges on the outside.

Click on images for larger view


Various decals indicating ORIA tube set in use

Entire tube set

Picture courtesy eBay seller chrispetso

Chart showing various versions of this tubing