Resealable Mylar Bags.

Press-to-close is the standard interlocking profile and the lowest cost, pull-tab adds a grip tab for a small uplift, and a slider gives one-motion closing at the highest price. A child-resistant version needs two coordinated actions to open and is tested to 16 CFR 1700.20.

We pick by open count. A bag emptied in a few uses can take press-to-close. A bag opened daily for a month wants pull-tab or slider, since the extra usability is what keeps the customer closing it properly every time.

No, a zipper alone is not airtight, which is why we heat seal a strip above it. The heat seal gives a true hermetic barrier from filling to first opening. After the customer tears that strip off, the zipper takes over and gives a good practical reseal between uses.

A zipper that does not close properly defeats the point of the film. That is why we spec track gauge rather than assume it, and why the tear notch has to sit above the zipper line so the first tear does not destroy it.

Above the zipper line, always. The notch guides the first tear across the heat-sealed top strip and leaves the zipper track intact underneath. If the notch sits low, the customer tears straight through the closure and the bag never resets.

We also leave clearance between the zipper and the fill line. Headspace keeps product out of the track during filling, and a clean track is the difference between a zipper that closes for a month and one that stops closing in a week.

Matte lamination, because it hides the fingerprints and handling marks a bag picks up over twenty openings. Soft-touch is a step up in feel that a customer notices every time they reach for the pack. Gloss gives saturated colour for busy retail shelves.

Spot gloss over matte gives a sheen-only logo. A clear window is useful on a multi-serve pack because it shows how much is left. Leaving areas unprinted on a metallised laminate gives a mirror-silver reveal.

Common sizes are 4 x 6, 5 x 8 and 6 x 9 inches, measured flat across the outside edges. The zipper and heat-seal strip take up the top inch or so, so the usable fill height is less than the bag height. We allow for that, plus headspace above the fill, when sizing to a weight.

Lay-flat pouches ship denser and cost less. Gusseted versions stand on a shelf and cost a modest premium. Send us the fill weight and a sample and we'll size it from there.

Five hundred per size and design is the starting quantity. Any of the zipper types can run at that number, though a slider or child-resistant assembly adds to the unit cost. Above 1,000 pieces the price tiers down.

Runs go to 100,000 without changing the construction. If you are choosing between zipper types, the sensible route is to sample two, put both in customers' hands for a fortnight and order the one that still closes cleanly at the end of it.

Production takes 7 to 10 business days once artwork is approved, or 5 to 7 business days on a rush. A sample takes 5 to 7 business days and the sample charge is credited against the production run.

Test a sample the way a customer would: tear the top, open and close it thirty or forty times, and see whether it still holds. A zipper that loosens in the test will loosen in the kitchen, and it is far cheaper to change the track now.

The laminate does the protecting and the zipper only has to return the bag to a closed state after each use. A metallised or foil structure blocks light and slows oxygen, and as long as the track closes fully the contents stay in condition between openings.

The weak point is the closure, not the film. A track that has stretched, or one clogged with product, leaves a gap the film cannot compensate for. Track gauge and headspace are the two specs we hold tightest on this format.