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Your cart is empty. Secure Seal: 4" x 4" x 3 Inches Mailers (Bulk 50 Pack)
A better quality of boxes made with better materials. We use 32-ECT-B crush-resistant corrugated cardboard to create a lightweight, cheap-to-ship, die-cut box that's strong enough to stand up to whatever you need it to. Each box is rated for an ultra-durable 32-ECT-B crush resistance and gives you the most cost-effective way to ship your packages possible.
All-Purpose
These boxes are perfect for mailing, storage, moving, and organizers. They have amazing durability for shipping and stacking to ensure the safety of whatever you package. These folding boxes come together easily without tape, glue, or staples. They're totally foldable and are complete with double-walled sides.
Secure Seal
Secure Seal provides a huge variety of boxes in large and small sizes perfect for whatever you need. Check out our Amazon store for a full selection of boxes! We're dedicated to providing better products, that stand up better, at cheaper prices.
Tanya
2025-08-28 18:08:59
Good quality, light weight for shipping
Customer
2025-08-14 16:38:51
These are essentially identical to the U-line S430 white shipping box of the same size. They arrived very fast, within 2 days. The large box containing the pack of 300 was not damaged, so no boxes were destroyed in transit. They are of similar cardboard thickness, color, and appearance to the U-line product, but at a lower price.
Milwaukee Cat Man
2025-07-16 14:57:20
These work great. I used them to organize my guitar pedals. I hav also shipped items with these boxes. Just this week I shipped chocolate chip cookies in this box.
Shawn
2025-05-08 12:07:05
Did have several bad ones out of 650 but great product regardless
Richelle L.
2025-04-19 18:23:50
The quality of these 6x6x1 boxes is the worst I've seen, and I've been purchasing boxes for my business for several years now. The first issue was that they were wrapped so tight in cling wrap that it bent all the skinny pieces of the box and quite a few were ripped. The second issue is the absolutely terrible quality of the cardboard -- it's so thin and flimsy and they do not stay together well or even resemble the square shape that they're supposed to be.I've tried to put together at least 10 of these boxes and none of them hold their shape, and I've had to throw away several due to the ripped pieces that are integral to putting the box together. This is the thinnest and cheapest quality of boxes I've ever purchased, and for this price I expected much better. I use this smaller size consistently for my business but will not purchase again from this supplier.
Stephanie Haussler
2025-03-20 15:08:32
We use these boxes to ship the glass marbles and tiny sculptures my husband makes. These are big enough to put an address label on and the postal label and that is about all that will fit on the box. Sturdy and just the right size/weight for what we need.
Carolyn L. Velando
2025-03-02 21:00:42
These small mailers are great. I love the way easy to assemble after the 1st try. I love them, perfect for small business and affordable. Thank you. PERFECT
Johnnie A.
2025-01-27 19:14:46
The boxes went together rather easily.
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