Uline carries the strongest boxes around.
- All Uline boxes have a "Bursting Strength" of at least 200 pounds per square inch.
- Bursting Strength is the only measure of box strength you should use.
Look at the "Box Certificate" seal to check what you have:

- Competitors may only use the Edge Crush Test (ECT) to determine box strength.
- ECT is a less rigorous test that measures stacking strength, not bursting strength.
- A box with an ECT of 32 may only have a Bursting Strength of 130 to 190 pounds.
- UPS recommends a box with a bursting strength of at least 200 lbs per sq inch.
- A 200 lb test box will better survive the punishment of being shipped than an ECT 32 box.
UPS Strength Guidelines
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