What are they?
Inserts are layers of absorbent fabric, usually sewn into a rectangular shape, that are used to create absorbency in diapers. Sometimes, you may hear the words insert and soaker used interchangeably. However, inserts are usually part of a pocket diaper or used with a cover, whereas soakers are usually part of a fitted, AIO or AI2 diaper.
A doubler is a thinner and smaller insert used to increase absorbency when paired with a regular insert. It often is part of a set that includes a larger "one-size" insert and a doubler. The doubler may be used alone for newborns (in fact, they are sometimes called "newborn inserts") or with another insert for heavier wetters and older babies. For the purpose of the rest of this article, doublers will be lumped in with inserts. A doubler is also sometimes called a booster.
Soakers are layers of absorbent fabric that are often sewn into the diaper itself, or the soaker may snap into the diaper. The term soaker may be used interchangeably with the term insert. However, soakers are usually components of a fitted, AIO or AI2 system. (A soaker can also refer to a wool diaper cover; however, for this article we're talking about the absorbent soakers.)
Liners are usually single-layer pieces of fabric (disposable or fleece, which is reusable) that are laid in a diaper to either create a stay-dry feeling (fleece only), to make disposing of poop easier (either disposable or fleece), or to protect the diaper when using a non-cloth-diaper-safe diaper cream (fleece is preferred but disposable may work as well).
The lining may also refer to what fabric is against the baby when referring to a pocket, AIO, or AI2 diaper.
What do they look like?
A hemp Artsy Fartsy Foo-Foo snake-style insert.
A microfleece liner.
A flip insert; stay-dry on one side and microfiber on the other.
A BumGenius doubler (AKA newborn insert)
An unsnapped soaker on a Fishnoodles diaper
A microfiber insert halfway pulled out of a pocket diaper.
A hemp insert in a BestBottoms shell.
A soaker in a Doodle Dypes AI2 diaper.
A soaker in a Tangerine Baby fitted diaper.
A soaker (sewn down at both ends, but pulled up in the middle for the picture)
in a BumGenius Elemental diaper.
in a BumGenius Elemental diaper.
A Flip disposable insert.
A disposable liner.
A prefold diaper tri-folded to use as an insert.
A Flip stay-dry insert sitting in a Flip cover.
A Flip disposable insert sitting in a Flip cover.
What are they made of?Inserts are often made of cotton, hemp, bamboo, microfiber, or Zorb.
Soakers may be made of cotton, hemp, bamboo, microfiber, or Zorb, and are often topped with either cotton velour (CV) or organic bamboo velour (OBV).
In general, hemp, cotton, or bamboo inserts may be trimmer then microfiber inserts, and may be more absorbent. However, microfiber is much cheaper. Some people have issues with microfiber trapping stink; usually this can be fixed with a good soak.
Liners, when referring to something that is laid into the diaper between the diaper itself and the baby, are made of either microfleece or a disposable tissue-like fabric.
Linings, when referring to the part of the diaper that is against the baby, may be made of fleece, microfleece, microsuede (all of which have a stay-dry feeling), cotton, hemp, bamboo, or velour (either cotton or bamboo), which do not have a stay-dry feeling.
Note: Microfiber products and Zorb I products CANNOT be placed against the baby's skin. They are over-drying and may cause irritation. They should only be used inside pocket diapers or, if topped with another fabric, with the microfiber side facing away from the baby.
How do I care for my inserts, soakers, or liners?
Synthetic fabric products like microfiber and microfleece need only be washed once prior to use. Natural fiber products, like hemp, must be washed 5-6 times prior to use. If the natural fiber is an insert without snaps, elastic, or aplix, you can boil it instead of washing it multiple times. Just boil for 10-20 minutes, then wash as normal. Some disposable liners can be re-used after washing if they were not pooped on; check the directions for the specific liners you are using. Some people have had issue with their septic systems when using disposable liners. When using re-usable liners to protect a diaper from non-cloth-diaper-safe rash creams, wash the liner separately with regular laundry.
What are common brands of inserts, soakers, or liners?
Most diapers come with the insert or soaker you will need to use. However, some people prefer to use an "aftermarket" insert for various reasons - they may want to replace their microfiber inserts for hemp inserts, they may want to add inserts for overnight, etc.
Artsy Fartsy Foo Foo - hemp inserts
Baby Kicks JoeyBunz (regular and premium) - hemp inserts
Swaddlebees - bamboo inserts
Rumparooz 6R inserts - hemp or microfiber
Hemp Babies - hemp inserts
BumGenius - microfiber inserts
Knickernappies Loopy Do and Super Do - mix of microfiber and hemp inserts
Bummis - fleece liners
Bumkins - disposable liners
*You can make your own stay-dry fleece liners by cutting up a piece of microfleece.