Uline
4 x 4 x 4" Corrugated Boxes S-4040, $.34
$.34checked Oct 9, 2026
Uline
Tear-Proof Polyethylene Mailers with Tear Strip - 9 x 12" S-3353
Self-seal 3 mil poly mailers, 9 x 12 in outside, with a tear strip; $22 per case of 100.
- 3 mil three-layer polyethylene, tear-proof and water resistant
- Self-seal adhesive closure and perforated tear strip
- Ink, stamps and labels adhere easily
- 100 mailers per case
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Before you buy: prices and stock change; confirm on the seller's page.
From a buyer's seat
Our analysis from specs, price and published reviews. Not hands-on.
Built from Uline's product page, checked Oct 9, 2026.
Tough, light poly mailers for soft goods, 9 x 12 in. One case of 100 costs $22, which is 22¢ a mailer, falling to 18¢ at 20+ cases.
Who it fits
Fits you if
- You ship apparel, textiles or other soft items
- You want a tear strip so customers open it cleanly
- You print or stick labels straight onto the mailer
Skip it if
- You ship breakable items: a box such as the 4 x 4 x 4 in cube protects better
- You need a waterproof seal: Uline says the seal is not water resistant
What it really costs
| Case of 100 (1 case)Uline price | $22 |
|---|---|
| Per mailer, 1 case$22 ÷ 100 | 22¢ |
| Per case at 3 / 5 / 10Uline quantity prices | $21 / $20 / $19 |
| Per mailer, 20+ cases$18 ÷ 100 | 18¢ |
Pick the size with Uline's rule: width = product width + thickness + 1 1/2 in; length = product length + thickness + 3 1/2 in.
Our math from seller prices checked Oct 9, 2026.
Your options
If your items are smaller
Tear-Proof Polyethylene Mailers with Tear Strip - 6 x 9" S-3352
Same mailer in the other size, also 100 per case.
If you ship breakable items
4 x 4 x 4" Corrugated Boxes S-4040
4 x 4 x 4 in boxes, $.34 each in bundles of 25.
How to spend less and get more out of it
- Size it with Uline's rule: product width + thickness + 1 1/2 in, and length + thickness + 3 1/2 in.
- The price per case drops at 3, 5, 10 and 20 cases.
- Shelf life is 1 year when stored between 40° and 100°F.
Verdict: Buy
Buy by the case; 22¢ a mailer at one case, 18¢ at 20 or more.
Tear-Proof Polyethylene Mailers with Tear Strip - 9 x 12" S-3353
$22 checked Oct 9, 2026
Some links are affiliate links. If you buy, I may earn a commission at no extra cost to you. Learn more
Buy at Uline (opens uline.com in a new tab)Key facts
| Brand | Uline |
|---|---|
| Category | Packaging |
| Outside (W x L) | 9 x 12 in, plus a 2 in flap |
| Thickness | 3 mil |
| Material | Three-layer co-extruded polyethylene, resin code #4 |
| Water resistance | Material yes; seal no |
| Per case | 100 mailers |
| Case weight | 3 lbs |
| Shelf life | 1 year stored at 40° to 100°F |
| Country of origin | USA |
| Price | $22 (checked Oct 9, 2026) |
| Source | uline.com (opens in a new tab) |
Facts are copied from the seller's page on the date shown.
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Tear-Proof Polyethylene Mailers with Tear Strip - 6 x 9" S-3352, $17
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Some links are affiliate links. If you buy, I may earn a commission at no extra cost to you. Details
$22checked Oct 9, 2026
Buy at Uline (opens uline.com in a new tab)