A team bag already closes. The flap folds over the back onto a factory adhesive strip, and that strip is the closure. A Serial Seal™ laid on top of it is not a better closure.
What the bag does not have is a name. Forty bags on a break table look identical, and the only way to tell them apart is to open them. A seal fixes that one thing: the bag becomes ACME-0417 instead of "one of the bags." The prefix and the number the run starts counting from are two fields you fill in on the builder, and the sheet arrives in sequence. At the sixty-seal minimum that is 50 cents a bag, and the rate falls from there.
The bag you are working with
The common hobby size is a resealable team set bag at 3-3/8" x 5" with a 1" flap on top, so the flat blank before the flap folds is about 3.375" x 6". There is also a tighter 3-3/8" x 4" variant for a single top loader. Capacity ratings vary by brand and between listings, so read the listing in front of you.
The material matters here: acid-free polypropylene, thin and slick. The mistakes section comes back to it.
The flap folds down onto the BACK face. Its free edge — the bottom edge of the flap, lying on the bag body — is the joint you are marking.
Where the seal goes
Use a single seal. Not a fold.
Lay it vertically on the back face with its midpoint on the flap's free edge. The seal is 1.77" long (44.958 mm), so centering leaves 0.885" above the edge on the flap and 0.885" below it on the bag body. The flap is only 1" deep, so the upper half of the seal lands across nearly all of it. That is about how much of the flap shows up in your photograph. It is not about holding anything shut. At 0.75" wide (19.05 mm) the seal takes a little under a quarter of the bag's 3.375" width, so it does not hide the contents.
A fold over the bag's top folded edge works geometrically, but it crosses the wrong joint. The top fold is not where the bag opens. The flap edge is.
If you want the wrap look anyway, do the arithmetic first. A folded seal does not put 0.885" on each face — that is the zero-thickness upper bound. Per-face landing is (1.77 - T) / 2, where T is the thickness of the loaded bag: 0.73" per face at 0.31" thick, 0.585" at 0.6". In our own handling, folds get unreliable somewhere below roughly 0.55" to 0.58" per face. That is bench experience, not a measured spec — fold one loaded bag from your batch before you commit to fifty.
| Single across the flap edge | Fold over the top edge | |
|---|---|---|
| Joint it crosses | The flap's free edge, where the bag opens | The top fold, which is not an opening |
| Landing | 0.885" on the flap, 0.885" on the body |
(1.77 - T) / 2 per face — 0.73" at T = 0.31" |
| Thickness sensitivity | None | Shrinks as the bag fills |
| Use it when | Always, on this format | You want the wrap look on a thin bag |
Because placement never varies on this format, the bag count is the seal count — forty bags on the table is forty seals, with no fold arithmetic sitting in between. The builder takes that number directly, along with the prefix and the start value the run counts from.
Step by step
- Load the bag first. Cards go in top loaders, top loaders go in the bag. You seal the holder or the bag, never the card.
- Photograph the loaded bag open, contents visible.
- Fold the flap down onto the factory strip and press flat from the fold outward so you do not trap a bubble.
- Wipe the back of the bag with a dry microfiber. Polypropylene collects finger oil, and adhesive does not stay on oil.
- Peel the seal and set it down vertically, midpoint on the flap's free edge. Land the middle first and let the ends follow. That keeps it straight.
- Burnish it. Thumb from the center out to both ends, twice. A seal only half down will lift in a mailer.
- Photograph the sealed bag with the serial legible, and date the file.
- Log the number against the order: serial, buyer, contents, date. A spreadsheet column is enough, filled in as you seal.
Steps 2, 7 and 8 are the ones doing the work. Step 5 is thin film with adhesive.
What a numbered bag actually gives you
The seal says nothing about the cards. A number on the outside of a bag cannot describe the inside of one, and it authenticates nothing. If your layout carries a VOID IF DAMAGED line, read it as a statement of the terms you are shipping under. It is a notice, not a mechanism.
The limit, in bag terms: the flap peels, the seal can come off with it, and the same cards can go into a fresh bag under a fresh seal. That is the honest ceiling on this format.
What the bag gets you that a blank sticker cannot is the number. You picked the prefix and the starting number, we printed the run in sequence, and no two seals in your order repeat. Photograph the sealed bag with the serial readable, write that serial next to the order, and you have a specific claim about a specific shipment instead of a general one. Skip the photo and the log line and the seal is decoration. Where a claim goes after that is not ours to promise — marketplaces run their own processes.
How many do you need
One seal per bag, and the bag leaves with the buyer. Nothing comes back to reuse, so seals sit on your list next to the bags and the mailers: a consumable you buy by the month, not a tool you buy once.
Count them off the bags themselves. Bags ship in packs of a hundred, and you know roughly how many packs a quarter goes through — break shipments, lots bagged for a show table, loose stacks that would otherwise go into a mailer bare. That pack figure is your seal figure, because placement never varies here: one bag, one seal, plus a handful for the ones you set down crooked.
Seals come in packs of twelve, and sixty is the smallest order. A bag is the cheapest thing in the chain — packaging, not something that follows the card — so the question is having enough. Two packs a quarter is 800 bags a year, which sits past 600 at 40 cents a bag — 804 seals, the next whole twelve, is $321.60. Three-quarters of that pace lands on 600 itself for $240.00 at the same 40 cents; both sit under half a dollar a bag. Below them, 120 is $54.00 at 45 cents, and the 60-seal minimum is $30.00 at the 50-cent list rate — a starter run rather than a supply. Forty cents is not the floor either: the rate keeps stepping down — 36 cents at 1,200, 33 cents at 2,400 — and holds at 30 cents from 4,200 on; self-serve tops out at 10,008 seals ($3,002.40), and bigger runs we quote the run rather than post a rate.
60 Serial Seal™ minimum · From $30.00 · As low as $0.30 each in bulk. No setup, die, or design fees. Commercial license and copyright included.
The rate steps down on quantity alone at checkout — no code to enter, and one tier at a time, so a single order of 600 costs less per bag than five orders of 120. Type your number into the builder and the per-seal rate for that quantity is on the screen before you pay.
Common mistakes
Sealing the bag when you meant to seal the card. The bag is the outer layer and does not stay with the card. For a number that travels with the item, seal the top loader inside instead: how to seal a top loader. For identifying a shipment or a show lot, the bag is the right surface.
Ignoring the substrate. Polypropylene is slick and low surface energy. A mild adhesive can release from it cleanly; an aggressive one can grip hard enough to tear the thin film and drag the factory flap strip with it. A shredded bag is a bad thing to hand a buyer. Seal one from the batch, leave it a day, then pull it, and you will know which you have.
Centering the seal on the flap instead of on its edge. A seal sitting entirely on the flap crosses nothing. The midpoint of the 1.77" goes on the free edge.
Putting adhesive on sealed wax inside the bag. If the bag holds a sealed pack, seal the bag and leave the wax alone. Adhesive on shrink film or a foil wrapper marks the pack itself. Keep the number on the outside.
Leaving the ends near the bag's outer edge. Lifted corners snag in handling. Keep the seal inboard, flat and burnished, or your buyer opens the mailer holding a half-stripped seal.
Questions people ask
Should I use a fold or a single seal on a bag?
Single. A flat seal centered on the flap's free edge lands 0.885" on each side no matter how full the bag is. A fold crosses the top fold, which is not an opening, and its per-face landing of (1.77 - T) / 2 only shrinks as the bag fills.
How many seals do I need for a break?
One per bag, plus a few for the ones you set down crooked. Count off the packs of bags you go through rather than aiming at a tier — the rate steps down on its own when you get there. The pack arithmetic and the rungs are in the section above.
What do I write down when I seal a bag?
Serial, date, buyer or lot, and what is inside, plus a photo of the sealed bag with the number readable. That record is what you rely on later, and the return fraud page covers how sellers use it.
Bags are the low-stakes end of this on purpose. Nothing about a team bag is precious, and a break shipment gets a number for well under a dollar. Break stacks apply the same habit to a whole shipment, and the full placement guide covers the formats living inside the bag.
If you are weighing this against a roll of plain void stickers, the two compared covers what separates them. What you are buying is a 0.75 x 1.77 in seal, printed in your sequence, one per bag. Sixty is the minimum order — $30.00, 50 cents a bag — falling to 40 cents at 600 and stepping all the way to 30 cents at 4,200, which is the floor for any larger run. Start from a gallery design on the seal builder, or put your own logo on the face at add a logo.
Serial Seal is an independent printer. We are not affiliated with, endorsed by or sponsored by PSA, Beckett, CGC, SGC, Ultra Pro, BCW, eBay, Whatnot, TCGplayer or any card manufacturer. Brand names are used only to describe the products they make. Nothing here is legal advice.