Question 1

Are the bags truly 12x16 inches inside, or is that the outer measurement?**

Accepted Answer

The 12x16 inch size refers to the bag’s external dimensions. The internal usable space is slightly smaller—about 11.5 x 15.5 inches—due to the gussets and seal flap. For reference, it comfortably holds folded clothes, A4 documents (if you fold the flap over), or items up to 3 inches thick. If you need exact internal fit, size up to the 14x18 version.

Question 2

Can I trust the self-seal for heavy items or international shipping?**

Accepted Answer

Yes, for most everyday parcels. The strong permanent adhesive holds well for items up to about 3kg (6.6lbs). However, a small number of buyers report seal failure on very heavy loads (4kg+) or after long storage. For international shipping, we recommend adding one strip of clear packing tape across the seal for extra security. They pair nicely with our 50-strong tape if you want reinforcement.

Question 3

How does the material compare to typical post office mailers or bubble-lined envelopes?**

Accepted Answer

These are opaque, lightweight polythene bags with a smooth finish—similar to standard postal poly mailers but slightly thicker (50 microns). They’re more protective than a paper envelope and more affordable than bubble-lined versions. That said, they’re best for non-fragile items like clothing, books, or documents. If you’re shipping glass or electronics, consider bubble mailers or double-bagging.

Question 4

Are these bags suitable for returns and online selling?**

Accepted Answer

Absolutely—they’re a favorite among eBay and Depop sellers. The simple peel-and-seal closure makes packing returns fast, and the neutral black color doesn’t show wear. One note: they’re single-use only. You’ll need a fresh bag for each parcel. If eco-friendliness matters, check our biodegradable mailer range (search “50 Strong eco”). For bulk sellers, the 100-pack offers the best per-bag value.

Question 5

What’s the max weight these bags can handle without tearing?**

Accepted Answer

Users consistently report safe shipping for parcels up to 3kg (6.6lbs) with normal handling. For heavier items, consider our 12x18 inch heavy-duty mailers (90 microns). The tear risk increases with sharp corners or rough transit—so avoid overpacking or use corner protectors for anything heavy or boxy. Many TikTok sellers recommend using two bags for very heavy clothing bundles.

50 Strong 12 x 16 inch Polythene Mailing Postal Bags Plastic Material Mailing Or Posting Parecels Bag For Postages Strong Self Seal

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