Buyers use the two names interchangeably, and suppliers don't always correct them. They aren't the same product. Both are polyethylene film, often run on the same extrusion and converting lines — but a poly mailer is built to be the parcel, and a poly bag is built to protect a product inside something else.
The poly mailer: the parcel itself
A mailer takes a shipping label and goes straight into the carrier network with nothing around it.
- Opaque film, so the contents stay private. Ours run in solid black, or white with a black inner face.
- A flap with a permanent adhesive strip: it seals once and ships as-is.
- Heavier film for the parcel network — 2.5 mil is our stock mailer gauge.
- The printed face is the outside of the shipment, which is why brands print them.
The poly bag: protection inside the shipment
A poly bag almost never ships alone. It goes inside a box, inside a mailer, or into an Amazon inbound shipment.
- Usually clear, so the product and its barcode can be seen and scanned.
- Open mouth or a self-seal lip, depending on how it's packed.
- Lighter film for the job — 1.25 mil on our perforated-roll bags, 1.5 mil on FBA warning bags.
- Protects against dust, moisture and scuffs in the warehouse and inside the box.
Where Amazon's poly bag rules come in
Amazon's poly bag requirements are written for the bag that packages a product for FBA — the clear inner bag. A bag 5 inches or larger needs the printed suffocation warning, the film must be at least 1.5 mil, and the bag needs vent holes. State suffocation-warning laws are a separate question; our FBA poly bag requirements guide covers both.
When an order needs both
Plenty of apparel brands use both: a clear bag around each garment for protection and scanning in the warehouse, then a mailer around the order for shipping. And a brand that sells through FBA while shipping its own direct orders typically needs warning bags for the Amazon inventory and mailers for everything else — two products, one supplier, one freight lane.
Choosing, one line each
All of them are made in our Tijuana plant, with extrusion, printing and conversion under one roof, and stock sizes ship from a single case. Tell us what you're packing and where it's going, and we'll quote the right one in 24 business hours.
- Shipping a soft product straight to a customer: poly mailer.
- Protecting a product inside a box or a mailer: poly bag.
- Sending bagged units into Amazon FBA: suffocation warning bag, 1.5 mil, vented.
- Bagging at volume at a pack station: poly bags on a perforated roll.