When I decided to introduce an all-in-two cloth diaper system at Lilly & Frank, I wasn’t interested in creating just another version of something that already existed. I wanted to solve some of the practical problems I had noticed with other cloth diaper styles.
My first consideration was cost.
I wanted families to be able to cloth diaper with fewer products by making each piece of the system reusable in more than one way. I also wanted a diaper that would fit well from the newborn stage through potty learning—without requiring parents to stuff pockets or wait for thick, sewn-in absorbency to dry.
The result was our Lilly & Frank all-in-two system: a familiar diaper-shaped shell with reusable, snap-in absorbency that can be adjusted as your baby grows.
What is an all-in-two cloth diaper?
An all-in-two, commonly called an AI2, has two separate parts:
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A waterproof outer shell
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A removable absorbent insert
The insert snaps directly into the shell rather than being stuffed into a pocket or permanently sewn into the diaper.
When the insert is wet but the shell is still clean, you can remove the used insert, give the waterproof interior a quick wipe and snap in a fresh one. This allows the same shell to be used for multiple diaper changes before it needs to be washed.
That reusability is one of the biggest benefits of an AI2 system. Instead of purchasing a complete diaper for every change, families can own fewer shells and more inserts.
Why I chose an AI2 system
Every cloth diaper style has advantages, but I kept coming back to the same question: how could I combine the best parts of several styles into one practical system?
Pocket diapers have a familiar shape—but require stuffing
Pocket diapers have a shape similar to a disposable diaper, which many parents find approachable. Once they are prepared, they are fairly simple to put on a baby.
The downside is that every absorbent insert must be stuffed into the pocket before the diaper can be used. Stuffing a full load of pocket diapers takes time—and time is something most parents are already short on.
The entire pocket diaper must also be replaced and washed after each change.
I wanted to keep the familiar shape parents appreciate without requiring them to stuff inserts inside a pocket.
All-in-ones are convenient—but can take longer to dry
All-in-one diapers are convenient because the absorbency is sewn directly into the shell. There are no separate pieces to assemble before putting the diaper on.
However, sewn-in inserts can be bulky at the smallest settings and may not sit as neatly on a tiny newborn. They also take longer to dry because the absorbency cannot be separated from the waterproof shell.
Removing the absorbency from the shell allows each part to be washed and dried separately. It also makes it easier to customize both the fit and absorbency at different stages.
Many AI2 covers use double gussets
Double gussets can be very helpful for adding containment and creating room over bulky fitted diapers. However, I have found that some double-gusset covers can be trickier to fit smoothly on very small newborns.
For the Lilly & Frank AI2, I started with the simple diaper shape parents already know and added specific fit features to help it adjust comfortably at every stage:
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Soft tummy elastic
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Wide back elastic
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Gentle leg elastics
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Double hip snaps
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Adjustable rise settings
I then added front and rear insert snaps to create the convenience and cost-saving benefits of an all-in-two system.
How do the Lilly & Frank inserts work?
Babies change considerably between the newborn stage and potty learning. One insert shape was unlikely to provide the best fit and absorbency at every stage, so I created two inserts that can work independently or together.
Stage 1 Infant Insert - 3 Layers (6 when folded)
The Stage 1 insert is designed for babies approximately 7–15 pounds.
It has a long, narrow shape that folds in half at the smallest setting, giving a newborn six absorbent layers without creating unnecessary bulk throughout the diaper.
As your baby grows, the Stage 1 insert doesn’t become obsolete. It can later be used as a booster with the Stage 2 insert when additional absorbency is needed.
Two Stage 1 inserts can also be layered together to create the absorbency needed for another complete diaper change.
Stage 2 Book Fold Insert - 4 Layers (8 when folded)
The Stage 2 insert is designed for babies approximately 15–35 pounds.
It opens like a book and folds to create eight absorbent layers. Its wider shape fills the larger diaper settings more effectively while still allowing the layers to separate for easier washing and drying.
For naps, overnight or heavier wetters, the Stage 1 and Stage 2 inserts can be used together, creating a total of 14 absorbent layers.
This is what I mean when I say I wanted every part of the system to remain useful. The Stage 1 insert begins as a newborn insert and later becomes a booster rather than something your baby simply outgrows.
Do you change the entire AI2 diaper every time?
This is the biggest misconception I hear about all-in-two diapers.
No, you do not necessarily need to change the entire diaper every time.
The inside of the Lilly & Frank shell is waterproof and wipeable. It does not have an absorbent fabric lining or a pocket that becomes wet during use.
Here is how I recommend handling different types of changes:
For a wet diaper
Remove the wet insert, give the interior of the shell a quick wipe and replace it with a fresh insert. If needed, you can allow the shell to air briefly while using another one in rotation.
For a contained poop
If the mess stayed completely on the insert and the shell is still clean, remove the insert, wipe the shell thoroughly and snap in a clean insert.
When the shell is soiled
If poop gets onto the shell, place both the shell and insert with your dirty diaper laundry and use a completely fresh diaper.
There is no set number of times that every shell can be reused. It will depend on your baby, the type of change and whether the shell remains clean.
One family told me they sometimes made it through most of the day using only one shell with their newborn because the inserts were so absorbent and the cover remained clean. That won’t happen every day or for every baby, but it shows how efficiently the system can work.
Does an AI2 mean less laundry?
You will still need to wash an insert after every use, but reusing clean shells means fewer bulky diaper covers need to be purchased and washed.
The inserts and shells also separate completely for washing and drying. The absorbent pieces can take the time they need to dry without keeping the waterproof shells in the dryer longer than necessary.
For families trying to reduce the size of their diaper stash, the reusable shell is especially helpful. Rather than purchasing one complete diaper for every change, you can build a system with fewer shells and enough inserts to carry you between wash days.
Can the Lilly & Frank AI2 fit a newborn?
The shell is designed to fit babies from approximately 6–35 pounds.
Getting a comfortable fit on a newborn involves more than simply making a diaper smaller. The proportions, elastic placement and amount of absorbency inside the shell all affect how neatly it fits.
The soft tummy elastic helps the front of the diaper sit comfortably against a small belly. The wide back elastic and double hip snaps help close gaps around the waist and legs. The compact Stage 1 insert provides newborn absorbency without filling the shell with an insert designed for a much larger baby.
Together, these features allow the diaper to begin small and adjust gradually as your baby grows.
Is an all-in-two diaper right for your family?
An AI2 system may be a good fit if you want:
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A reusable waterproof shell
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Fewer covers to purchase
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No pocket stuffing
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Removable absorbency for easier drying
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Inserts that remain useful as your baby grows
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A familiar diaper shape with adjustable snaps
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The ability to customize absorbency for daytime, naps and overnight
Like any cloth diaper style, an AI2 doesn’t have to be used exclusively. You can use cloth part-time, combine it with disposables or keep a different diaper style for overnight.
The goal is not to follow one perfect cloth-diapering routine. It is to create a system that works for your baby, your budget and your everyday life.
That was my intention when I created the Lilly & Frank AI2: fewer pieces to buy, more ways to use them and a diaper that remains practical from the smallest setting through potty learning.
What if my baby needs a roomier cover?
As babies grow, some families eventually need more room for overnight absorbency, fitted diapers or a heavier-wetting child.
I designed the Lilly & Frank double-gusset cover with the same front and rear insert snaps used in our AI2 shell. This means families can continue using the Stage 1 and Stage 2 inserts they already own rather than purchasing a completely separate absorbency system.
The roomier shape and double leg gussets provide additional space and containment when it is needed, while the compatible snaps allow the cover to work as part of the same flexible system. A Stage 2 insert can be used on its own, or a Stage 1 insert can be added as a booster or a second Stage 2 if that is what your baby's absorbency needs are for naps and overnight.
Your baby’s needs may change, but the inserts you invested in can continue changing with them.
Not sure where to begin? Our AI2 starter bundles include the covers and inserts needed for approximately one day of cloth diapering, making it easy to try the system without committing to a full-time stash.