An All in One Nappy (AIO) is a nappy where the absorbency has been sewn onto the water resistant layer (PUL)
The absorbency might be sewn in both ends or just one end of the nappy
Nappies where the absorbency is sewn in at both ends take longer to dry than ones that are not
The idea is that all in one nappies need little preparation and simply go on the bum all in one piece
All in one nappies are very quick to prepare, they are all sewn together so nothing detaches in the wash so nothing to sort, find or stuff once dry.
They fit all in one piece and ones where the absorbency is sewn in at both ends and can be put on the bum “as is” can be a foolproof nappy for grandparents, carers or nursery.
The down side for all in ones, especially those sewn in both ends is drying time, as nothing can be detached and put in the tumble drier, and if air drying there is less airflow around the absorbent materials.