Expansion Poly Mailers

Sizing Note: All dimensions shown below are outside dimensions. Allow additional room for the thickness of your product when selecting a mailer size.
Image SKU Dimensions Mailers/Case
Price/Case
1 5 10
Add To Cart
10 x 13 x 2 PH-221157 10 x 13 x 2" 100
$15.81 $15.38 $14.96
11 x 13 x 2 PH-221163 11 x 13 x 2" 100
$27.81 $27.04 $26.31
11 x 13 x 4 PH-221165 11 x 13 x 4" 100
$23.09 $22.44 $21.84
13 x 16 x 2 PH-221179 13 x 16 x 2" 100
$38.07 $37.01 $36.01
13 x 16 x 4 PH-221181 13 x 16 x 4" 100
$25.64 $24.93 $24.26
15 x 20 x 4 PH-221199 15 x 20 x 4" 100
$34.83 $33.86 $32.95
20 x 24 x 4 PH-221207 20 x 24 x 4" 100
$55.16 $53.63 $52.18
26 x 28 x 5 PH-221209 26 x 28 x 5" 100
$86.07 $83.68 $81.42

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Bottom-Expansion Poly Mailers for Bulky Soft Goods

Expansion poly mailers add bottom depth to accommodate thicker products more naturally than a flat shipping bag. The third dimension can suit bulky apparel, textiles, catalogs and other compatible goods that remain appropriate for flexible packaging. Select width, length and depth from the finished product and keep the closure free of gusset pressure.

Size All Three Packed Dimensions

Measure the item at its widest, longest and deepest points after folding or adding inner protection. Listed dimensions are outside measurements. Choose the smallest expansion that loads comfortably, since excess gusset material can fold unpredictably and too little depth can pull on seams or distort the adhesive flap.

A bottom expansion adds capacity but not rigidity. Compare flat and specialty poly mailers for thinner products. When the item needs edge support or crush protection, use a corrugated mailer or box even if the expansion bag has enough volume.

Shape the Gusset Before Sealing

Open the bottom gusset fully and settle the product into the available depth without trapping sharp corners in a fold. Smooth excess film away from the seal area, then close the flap on a clean, dry surface. Check that the filled package remains stable enough for labeling and handling.

Expansion film can still puncture, stretch or flex around rigid contents. Protect protrusions and avoid treating the depth dimension as a weight rating. Test the completed package for seam pressure, product movement and the expected distribution route before standardizing a size.

Expansion Poly Mailers FAQs

What does the third expansion-mailer dimension represent?

It identifies the available bottom depth or gusset dimension for thicker contents.

How much expansion should I choose?

Use the smallest depth that loads comfortably without stressing seams or the closure.

Does expansion make the mailer rigid?

No. It adds capacity while the package remains flexible.

How should the bottom gusset be packed?

Open it fully, settle the product into the depth and keep folds away from sharp corners.

Need Help Choosing Expansion Poly Mailers?

Packaging HERO can help you compare width, length, bottom expansion, closure and product structure.

Contact Packaging HERO