
Corrugated Cardboard
Corrugated cardboard has a fluted middle layer sandwiched between two flat liner sheets. The flutes form connected arches that resist crushing, bending, and impact forces. This is why corrugated dominates shipping boxes, mailer cartons, and any application where the box needs to survive courier handling. Available flute profiles include E-flute (1/16 inch, best for printing), B-flute (1/8 inch, good crush resistance), C-flute (3/16 inch, standard shipping), and double-wall combinations for heavy loads. ECT (Edge Crush Test) ratings run from 23 to 71+ depending on configuration. Corrugated ships flat and pops open without tools.