Pocket nappies consist of a waterproof outer and a fleece inner. There's an opening along the back of the nappy through which you can insert as much (or as little) absorbency as you require. They are very simple nappies to use, and usually very quick drying. You should also consider longevity of all in ones. All in ones are washed after every use so the waterproof cover will undergo more washing than a two part system. All in one nappies are unlikely to last more than one child so if you are planning more children they might not be the right nappy for you. They don't provide the same level of containment or absorbency as a two part system however they are very quick and simple to use and are ideal for childcare or the change bag.