Correx® is the brand name for a dual walled extruded polypropylene sheet. It is sometimes referred to as corrugated plastic. However, it differs from corrugated cardboard which is made of three separate layers, corrugated plastic is a single piece, with two flat printable faces with open pipes running through it known as ‘flutes’. It is the size of these flutes which give the Correx® it’s thickness.

The preferred usage of Correx® differs depending on the chosen thickness. In its thinnest form of 2mm, it is often used for packaging. At the thickness most popular with printers, 4mm Correx® is used for small short-term outdoor signs and point of sale products. Thicker Correx® at 6mm and 8mm is generally used for larger forms of signage where the additional thickness gives better rigidity.