30″ X 17″ X 17″ Heavy-Duty Corrugated Box, Double Wall, 350#DW/ECT-51

Box Strength

Our corrugated boxes feature a box strength rating, such as #200/ECT-32B.

• The #200 refers to the Mullen Bursting Test rating which measures the bursting strength of the corrugated linerboard. For example, a box rated 200# can withstand 200 lbs. per square inch of force applied to the linerboard on the face of the carton.
• ECT-32 refers to the Edge Crush Test (ECT) rating. This number indicates the force the load bearing edges can withstand before they buckle, usually measured in lbs. per lineal inch.
• B refers to the flute strength. Flutes are the middle layer of the corrugated board that is structured in a wave pattern. The flute strength may not be included in these ratings.

The Mullen Test box criteria is better suited for the protection of heavier contents while the Edge Crush Test box is a better indication of good stacking characteristics.

Box Measurements

Box measurements are always expressed in three dimensions (Length x Width x Depth) and always in that specific sequence. These measurements always relate to the interior dimensions of the box.

• The length and width are the opening dimensions of the box, and the length is always the larger of the two (unless they are equal).
• The depth is how far you can reach into the box, and is the distance measured perpendicular to the length and width.

When measuring your box always leave space on all sides and above and below product for cushioning, such as bubble cushioning or loose fill. Our guide to box types can help you choose which is best for shipping for products.

Corrugated Cardboard is typically comprised of a fluted or zig-zag paperboard layer sandwiched between two stiff boxboard layers. Used in the manufacture of shipping cartons, corrugated material offers increased reinforcement to protect box contents from damage. Corrugated cardboard material is offered in single-face and single-wall configurations. For added strength, double- and triple-wall configurations are available. The fluted layer can also vary according to flute depth and number of flutes per foot.