Bumgenius are a world renowned brand of cloth nappies, with outstanding quantity, and comfort for your baby. Bumgenius nappies have a patented butterfly closure system for maximum comfort. 
These Elemental nappies are an all in one nappy with super absorbent organic cotton. They are a One Size nappy so they would fit your baby from approximately 8 to 35 pounds. (hence the term birth to potty!) With 3 different size settings achieved by the poppers at the front of the nappy this will allow you to adjust the size for your growing baby. 
Often newborn babies have such skinny legs it can be difficult to get a good fit. At about 6 weeks of age most babies will get a really good fit in a birth to potty nappy.
As elemental nappies have untreated organic cotton, it contains natural oils. It can take a number of washes initially for these natural oils to go and for the absorbency to by working at its best. Remember to never use fabric softener when washing your nappies as this will decrease the absorbency.
If you are expecting a very small baby and you would like to use reusable nappies from day one, you can try the Bumgenius Little here