Most nappies have the same layers in the same order:
Stay Dry Layer – closest to babies skin:
this can be built-in, reusable fleece or disposable. NB This is optional if not built in to the nappy.
Absorbency – the bit that catches the wee: this can be built-in, removable or disposable.
Absorbent layers and boosters are usually either:
Microfiber (mf) - quickly absorbent but can leak if compressed
Cotton – quickly absorbent and holds better than mf
Bamboo - slower to absorb, holds better than mf
Hemp- can be slow to absorb, but is very retentive. Will contain a % of cotton
Waterproof Outer – the wrap or shell that keeps it all in:
this can be built-in or removable. If the nappy feels plasticky or crinkly, that will be the waterproof layer.
Nappy wraps/shells/outers are usually made from:
PUL: polyurethane laminated fabric -this is the most common material: it's very waterproof, but if nappy is soaked, may wick through stitching
TPU: thermoplastic polyurethane: similar to PUL but more breathable
fleece: this repels moisture but allows evaporation
wool: this works like fleece
Fastenings - Most reusable nappies are fastened in one of 4 ways:
poppers or snaps
hook and loop (such as Velcro or Aplix)
using a nappy nippa (such as Snappi)
lengths of fabric which tie the nappy on
These are nappies that are made of cloth that is already shaped to fit baby, fastening with poppers, velcro or nappy nippa. These need a waterproof cover.
All in Ones/Twos (AI0/AI2)/Pockets
These have the waterproof cover attached to the piece of cloth either permenatntly (AI0), or with a fastening i.e poppers (Ai2), or a pocket to insert a cloth absorbency layer.
Terries & Prefolds
These are squares/ retangles of cloth that you fold in different ways around baby and fasten with a nappy nippa. These need a waterproof cover.