Poly Bags

How to choose poly bag thickness (mil)

A "mil" is one-thousandth of an inch. Thicker bags resist punctures and tears but cost more per unit and take more storage space, so match the mil to the weight and edge profile of what you are bagging — not to a blanket "thicker is safer" rule.

Rule of thumb: go up a mil when contents have hard corners, sharp edges, or ride in a bin against other parts. Stay lighter for soft goods where clarity and cost matter more than puncture resistance.

Poly bag types

Flat poly bags (open-end)

The workhorse of the family. Two flat panels sealed on three sides with an open top; you load, then close with tape, a heat sealer, or a twist tie. Best for flat or low-profile items — apparel, printed material, parts — where you want maximum clarity and the lowest cost per bag. Buy in bulk by width × length and mil.

Gusseted poly bags

Flat bags with expandable side or bottom folds (the "gusset") that open out to hold three-dimensional, bulky, or tall items without stretching the seal. The gusset dimension adds depth — a 10×8×24 gusseted bag holds far more volume than a flat 10×24. Use for bakery, produce, rolled goods, cylindrical parts, and anything that would bulge a flat bag.

Reclosable (zipper / seal-top) bags

Flat bags with an integrated press-to-close zipper track so the bag can be opened and resealed. Ideal for parts organization, sample kits, retail resale, and anything the end user needs to reopen. Available in the same 2–4 mil range; heavier reclosable stock holds up to repeated opening in industrial settings.

Poly tubing (layflat)

Continuous open-ended plastic tubing on a roll. You cut and seal to any length on demand, which lets one SKU cover many bag sizes — the most flexible option for high-mix operations and long or irregular items. Requires a heat sealer to close each end.

Clear vs. UV / anti-static, and which bag type to pick

• Clear poly is the default: it lets scanners read barcodes and lets customers see the product. Standard for retail and fulfillment.
• UV-resistant (UVI) poly is treated to slow sunlight degradation — specify it for items stored outdoors, in yard inventory, or under skylights.
• Anti-static poly protects electronics and static-sensitive components; use it instead of standard clear for boards, drives, and sensors.
• Flat vs. gusseted vs. reclosable: pick flat for thin/soft items and lowest cost, gusseted when the item has real depth or volume, and reclosable when the bag must reopen. Choose tubing when you need to make many odd sizes from one stock.

Related collections: Poly Mailers for shippable bags with a self-seal flap, Corrugated Boxes for rigid protection, and Void Fill to cushion bagged items inside a carton. Need a volume price or a custom size? Request a bulk quote.

Frequently asked questions

What does "mil" mean for poly bags?

A mil is one-thousandth of an inch (0.001"). A 4 mil bag is twice as thick as a 2 mil bag. Higher mil means more puncture and tear resistance at a higher cost per bag.

What is the most common poly bag thickness?

2 mil is the most widely used weight across retail and general shipping — it balances clarity, strength, and cost. Step up to 4 or 6 mil for heavy, sharp, or industrial contents.

What is the difference between a flat and a gusseted poly bag?

A flat bag is two flat panels sealed on three sides. A gusseted bag adds expandable side or bottom folds so it opens into a box-like shape, holding bulky or three-dimensional items without stressing the seal.

When should I use a reclosable bag instead of a flat bag?

Use reclosable (zipper / seal-top) bags whenever the bag needs to be opened and closed again — parts kits, samples, retail resale, or organizing components. Flat bags are a one-time seal.

What is poly tubing used for?

Layflat poly tubing is a continuous roll you cut and heat-seal to any length. It lets one stocked roll cover many bag sizes, which is efficient for long, irregular, or high-mix items.

Are these poly bags food safe?

Many low-density poly bags meet FDA requirements for direct food contact; food-grade status is called out at the product level. Check the individual product spec before using a bag for food.

How are poly bags sold — individually or by the case?

They ship in bulk case packs. Case counts vary by size and mil and are listed on each product. Larger case volumes qualify for free-shipping tiers.

Do you offer custom poly bag sizes or printing?

Custom sizes and print are available on volume orders. Send your dimensions, mil, and quantity through the bulk quote request.

Which bag protects electronics?

Use anti-static poly for boards, drives, and static-sensitive components rather than standard clear poly.

Do clear poly bags let barcodes scan through them?

Yes. Standard clear poly is transparent enough for scanners to read a barcode through the bag, which is why it is the fulfillment default.