A magnetic acrylic holder is two halves held together by magnets in the corners. It opens with your hands in about a second and leaves no mark on the shell. That is the appeal of the format, and it is what to keep in mind when you put a numbered Serial Seal™ on one. One seal size covers every point size on the shelf, so what changes between a 35PT run and a 360PT one is the count, not the seal.
This guide is about the card holder, also called a one-touch holder or a magnetic case. If what you have is the big acrylic display case a sealed Elite Trainer Box slides into, that one is covered in where to seal an ETB acrylic case and in the short section near the end.
What you actually have
Two acrylic halves, slide-in hinges on some versions, magnets in the four corners. The parting line runs around the whole perimeter at the mid-plane of the thickness, and there is no seam on either face.
Point sizes trip people up. The number is the inner opening in thousandths of an inch, not the outside thickness, and brands hang different ladders off similar parts, so 130PT from one does not map onto 130PT from another. Outside dimensions are worse, because most manufacturers do not publish them. Retailer figures put the standard-card versions at roughly 0.20 inches deep at 35PT, rising to about 0.60 at 360PT. Measure the holder in your hand.
Where the Serial Seal™ goes
Use a FOLD. The seal is 0.75 x 1.77 inches (19.05 x 44.958 mm), and a fold wraps it over an edge so part of it lands on each face — which puts the number in frame from the front and the back at once, the whole trick on a holder that gets photographed from both sides. A SINGLE seal lying flat on the back face works too, and is the cleaner look if the front must stay bare acrylic.
Work the landing out first. Per face it is (1.77 - T) / 2, where T is the thickness of the edge you are wrapping — on this format, the outside depth of the holder. The 0.885 inches per face people quote assumes an edge with no thickness, which nothing on this shelf has. Run the formula on your own measurement; the rows below only show how fast the landing shrinks.
| Point size | Approx. outside depth | (1.77 - T) / 2 |
|---|---|---|
| 35PT | 0.20 in | 0.785 in |
| 130PT | 0.33 in | 0.720 in |
| 180PT | 0.40 in | 0.685 in |
| 360PT | 0.60 in | 0.585 in |
From our own bench handling: under about 0.55 to 0.58 inches of landing per face, the fold gets fussy on acrylic and wants to lift at the crease. That is our experience with this stock, not a measured threshold.
Keep the fold at least 0.5 inches in from any corner. The magnets sit there, the shell is thickest and least flat, and a seal bridging a magnet pocket will dimple.
Which face gets the number
The serial lands on whichever half of the 1.77 inches ends up face-up, so decide before you press. On a display piece, run the number onto the back and leave the front to the card. On something going to a buyer, run it onto the front, low and off the card image, so it shows in your listing photo.
Portrait and landscape are a per-run choice rather than a per-seal one, so lock the orientation to the face you have just chosen when you lay the run out on the builder. Shelf pieces and listing pieces tend to want opposite orientations, so they come out cleaner as two runs than one.
Step by step
- Load the card and close the holder first. Adhesive goes on the holder, never on the card.
- Test one seal on a spare holder of the same brand before you commit a hundred.
- Wipe the edge and both landing zones with a dry microfibre. No alcohol, no solvent cleaners. Acrylic hazes.
- Pick the edge. All four cross the joint, so take the one that keeps the seal clear of the card image, and mark an offset at least 0.5 inches in from either corner.
- Lay the face-up half down first. Press from the middle outward, roll over the edge, then press the second half.
- Burnish the crease with a thumbnail or a bone folder. That is where a seal lifts first.
- Photograph the holder with the serial legible and log that number against the order. The record is the part that does any work.
What this does and does not do
A seal on a magnetic holder does not prove the card inside is real, does not prove the holder was never opened, and does not authenticate anything. It is printed thin film with adhesive, carrying a number.
The plain version for this format: a magnetic holder opens by hand. Two halves, four magnets, no glue, no welded shell. Someone can open one, close it again and put a different seal on it. What they cannot do is produce the serial you printed and photographed. You choose the prefix and the starting number, we print the run in sequence, and no two seals in your order carry the same one. Without the photo you are shipping decoration.
Some layouts print VOID IF DAMAGED, which is a notice rather than a mechanism; the FAQ puts it the same way. Marketplaces and grading companies decide their own cases their own way; if disputes are why you are here, the return fraud page is more use than this section.
How many do you need
The unit here is one seal per holder, not one per card. One fold, one serial, one row in your log. If you fold two opposite edges you are on two per holder, so decide that first, because it doubles everything below.
60 Serial Seal™ minimum · From $30.00 · As low as $0.30 each in bulk.
Then count in the thing you already buy. Holders come in packs of 10, 25 and 50, so multiply your usual pack size by the packs you empty in a year. One 25-pack a month lands on 300, which prices at $135.00 on the 120-plus rate, or 45c a seal. Four 50-packs a year is 200, which rounds up to 204 in twelves and lands at $91.80 — the same 45c a seal. Add half a dozen for the spares you test placement on, and if you decided on two folds, double the lot — that takes the 25-pack-a-month buyer to 600 at $240.00, or 40c each.
Your number will come out smaller than it would for sleeves or top loaders: a holder that costs a couple of dollars goes on a card worth putting in one, not on everything in the box. That usually lands the arithmetic in the low hundreds, which is the stretch of the ladder where the rate moves fastest: the climb from the 60-seal minimum to 600 takes 10c off every seal, and the steps keep coming after that until the rate bottoms out at 30c at 4,200.
The 60-seal minimum is $30.00, or 50c a seal — the right size for testing the fold on your own holders and not much else. Seals come in packs of twelve and the rate steps down on its own at checkout. There is no code to enter, and only one tier applies to an order. No setup, die, or design fees, and a commercial license and copyright come with the run. Put your number in on the builder and the run prices itself.
Common mistakes
- Treating one fold as coverage of the whole holder. One fold covers less of the object than the picture in your head suggests. Two folds on opposite edges put two numbers on the holder and two things in the photograph — a record benefit, not a barrier.
- An aggressive adhesive on acrylic. Solvent-carrying adhesives craze and haze acrylic permanently, and on a display holder that damage sits over the card image. Low tack, tested first.
- Covering the card window. On a 130PT holder the seal takes 0.720 inches of the front face. Keep it above or below the card, not across it.
- Landing on a corner magnet. The seal tents there, lifts in transit and arrives looking like a problem that never happened.
- Sealing a holder that is going to a grader. We do not seal anything heading for submission. Grading companies publish their own intake requirements and change them, so send the card the way they currently ask. The semi-rigid card saver guide covers submission-bound holders.
If yours is the large acrylic box case
A case built for a whole Elite Trainer Box is a different animal: roughly 7.9 x 6.9 x 3.9 inches, with a lift-off magnetic lid and no thin edge to fold over. Use a SINGLE seal laid flat across the lid-to-base joint on a side face. Nothing is wrapped, so the fold formula does not apply and the seal splits about 0.885 inches either side of the joint. Run one on each of two opposite sides so both photographs carry a number.
Leave the wax alone inside the case. No adhesive on sealed wax, on shrink film or on the box itself, for the reasons in the sealed wax guide.
Questions people ask
Will a Serial Seal™ damage an acrylic card holder?
It can. Acrylic hazes under aggressive adhesives and the marks do not buff out. Test on a spare first and keep the seal off the card window.
What size Serial Seal™ do I need for a 360PT holder?
The same one. Folded over a 0.60-inch edge it lands 0.585 inches per face, about the shallowest landing we would trust on acrylic. For anything deeper, bag or box the holder and seal that. The format-by-format guide has the numbers for the rest of the shelf.
Does a Serial Seal™ stop someone opening the holder?
No. Magnets let go by hand and a piece of adhesive film does not change that. What you have afterwards is a serial you can point to in a dated photo, which is a different thing from a lock.
A display holder is looked at as much as the card inside it, and that is what a number gets you here: the same serial in the shelf photo, in the listing photo and in the row you wrote down, all of them pointing at one holder. Three hundred seals is $135.00, or 45c each, and the 60-seal minimum is $30.00 if you would rather fold one over your own acrylic first. Designs and starting numbers are set on the builder; your own artwork goes on from the add a logo page.
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.