Abena m4 diapers is the phrase people type when the old case said M4 and the next order has to match that code. Abri-Form and Abri-Flex are both Abena names, and they are not the same garment. These notes do not include a price, a waist, a count, or an absorbency number for Abri-Form, Abri-Flex, M4, or L4. Nothing here was worn and scored.
Abri-Form is the tape brief. Tabs close at the sides, so a change can happen in bed or in a chair without pulling a waistband to the ankles. Abri-Flex is the pull-up, the one listings often call pants. It has to be stepped into and pulled down later. If the person you reorder for cannot do that, Flex is the wrong carton even when the brand and a familiar code sit on the front. The gain is at the hips.

M4 on the old bag is a code, not a clothing size you already know from shirts. L4 is a different code. Treating the letter as small, medium, or large from some other brand is how a case arrives that will not close. The listing you buy has to repeat both the line name and the code. A tile that says only Abena, or only briefs, can be either garment. Open it and look for Abri-Form or Abri-Flex, then for M4 if that is what the last pack printed.
The same search drags in other Abena words. Underwear, briefs, pants, Delta-Form, and Abri-Man are separate products. Abri-Man shows up in that brand search, often beside the word pads, so read the title before treating it as a brief or a pull-up. If a page will not show the code in the title or the bullets, leave it. A product photo is not a chart. Measure where the band will sit and use only the chart on that page, the way how to use a size chart describes. Inches copied from another brand are not Abena inches.

Tape brief or pull-up
Keep the two carts separate. Order Abri-Form when the last case was a tape brief, or when the person who helps with changes needs tabs. Order Abri-Flex when the wearer gets a pull-up on and off alone and the old pack was Flex. Style before the case count. A bigger case of the wrong style is a bigger miss. The general split is in pull-up underwear or tabbed briefs.
Refastenable tabs can be opened and pressed again if the first stick sits crooked. One-time tape cannot. If you are changing someone else, check which closure the Abena title actually names before you subscribe. That difference is spelled out in refastenable tabs and one-time tape. Photograph the front of the empty pack, including the code, and keep it with the reorder note in how to reorder for a parent.
Where to buy is the listing you have open once the title says Abri-Form or Abri-Flex and the code matches. Do not let a subscription renew a Flex carton because the brand matched and the price looked familiar. If two M4 tiles disagree about tabs, they are not the same product. Buy one bag of the one that matches the photo, wear it through a day of changes, then set the next delivery.
What a priced tape brief and a priced pull-up look like
These notes have no Abena price to put next to that decision. They do have a tape brief from another brand, which is only an example of a tab listing. LivDry EnduraDry Max tab briefs, medium, 16-pack, showed $42.99 when this article was written. Check Amazon before you pay. The listing says up to 12 hours, and the bullets call the cloth latex-free and breathable. Medium is the only size here, with no waist in inches, so none is invented, and medium is not a stand-in for M4. Sixteen into $42.99 is about $2.69 a brief if the price holds. The note on that pack is LivDry tab briefs in medium.
A pull-on with a printed waist is the other example, and it is not Abena either. Prevail Daily Protective Underwear, maximum, large, 64 count, showed $53.67 when this article was written. Check Amazon. The 64 count is four packs of 16. Large is listed for waists of 44 to 58 inches. The page says day or overnight, and it mentions breathable zones and aloe. The wearer has to get it on and off. Sixty-four into $53.67 is about 84 cents each. That math is for this pull-on only. It is not a guess at Abri-Flex. The waist is not an M4 chart. See Prevail Daily in large.
Match the line and the code on the empty bag. Leave LivDry and Prevail Daily in their own carts. Recheck $42.99 and $53.67 on Amazon if you were only using them to see what a priced title looks like. A first Abena order should be one pack whose code you can read.