Uline S-4398 Equivalent: 18 x 18 x 6" Flat Boxes (15-pack)
Model-to-size mapping verified against Uline’s published catalog listings on July 31, 2026; the Packrift price below is our live catalog price.
Uline model S-4398 is a 18 x 18 x 6" flat box per Uline’s published listings. The Packrift exact-size equivalent — same length × width × height, same grade class — is 18x18x6 ECT-48 Double Wall Kraft Boxes - Heavy-Duty Shipping (Bundle of 15), priced at $80.97 per 15-pack ($5.40 per box) today.
| Size | Grade class | Pack | Price today | Per box | |
|---|---|---|---|---|---|
| Uline S-4398 | 18 x 18 x 6" | Flat Box | see your invoice | see your invoice | — |
| Packrift equivalent | 18 x 18 x 6" | Flat Box | 15 | $80.97 | $5.40/box |
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Frequently asked questions
Is this the same box as Uline S-4398?
It matches S-4398’s published dimensions (18 x 18 x 6") in the same grade class, so it packs and stacks the same. It is not manufactured by or affiliated with Uline — when replacing a certified spec, match the certificate stamp printed on the box.
What if my Uline model isn’t listed here?
The cross-reference currently covers 634 verified models across boxes and mailers. Enter yours in the lookup tool, or request a quote with the model number and we’ll match it by spec.
Uline is a registered trademark of Uline, Inc. Packrift is not affiliated with Uline; model numbers are referenced for size-compatibility comparison only.