Corrugated galvanised iron (CGI) or steel, colloquially corrugated iron, wriggly tin, pailing, corrugated sheet metal, zinc or custom orb / corro sheet (Australia) is a building material composed of sheets of hot-dip galvanised mild steel, cold-rolled to produce a linear ridged pattern in them. Although it is still popularly called "iron" in the UK, the material used is actually steel, and only the surviving vintage sheets may actually be made up of 100% iron. The corrugations increase the bending strength of the sheet in the direction perpendicular to the corrugations, but not parallel to them, because the steel must be stretched to bend perpendicular to the corrugations. Normally each sheet is manufactured longer in its strong direction.

The Citroën H-Type vans, are a series of panel vans and light trucks, produced by French automaker Citroën for 34 years - from 1947 through 1981. They are notable for their industrial design, using many corrugated metal outer body panels to save material, weight, and costs. Early models of the uniquely styled trucks were just named Type H, but soon they were differentiated by a second letter, using the last four letters in the alphabet – except for the type HP for (flat-bed) pickups. Thus the vans were built as the types HW through HZ – with the majority of them built as Citroën HY.