馃搮 June 25, 2026 -6 min read -By Pebag Factory
Walk into any packaging warehouse and you'll see poly bags in a dozen variations. Three types account for most orders: flat bags (open top), zip lock bags (resealable), and self-adhesive bags (peel-and-seal).
Each one solves a different problem. Here's how to choose.
Open top, heat-seal or tie
Lowest cost per bag
Double-track zipper, reusable
Best for repeated access
Peel-and-seal, no equipment
Clean, professional look
A flat bag is exactly what it sounds like: a simple bag with an open top and a sealed bottom (or side). No closure mechanism -you fill it and seal it with a heat sealer, tape, or tie.
A zip lock bag has an integrated double-track zipper at the opening. Press to seal, pull to open. Can be reused hundreds of times.
Self-adhesive bags (also called peel-and-seal bags) have a strip of adhesive covered by release paper. Peel the paper, fold the flap, press -sealed. No heat, no zipper.
Two sub-types exist: peel-and-seal (adhesive strip on flap) and fold-over flap (tuck-in closure without adhesive).
Need the bag to be resealable? 鈫?YES: Zip lock bag (repeated access) or self-adhesive (single reseal) 鈫?NO: Flat bag (lowest cost)
Have a heat sealer on hand? 鈫?YES: Flat bag -fastest and cheapest 鈫?NO: Self-adhesive (peel-and-seal) or zip lock
Selling to end customers directly? 鈫?Zip lock or self-adhesive: better perceived value 鈫?Flat bag if it's inside another package (e.g., garment box)
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