NB or Small diaper?

Hi mga mommies. Team May here, wala pa talaga ako masyadong nabibili for baby. Not expecting the lockdown talaga. Anyway, ask ko lang po. Ano mas better bilhin ng marami? NB size diaper or the Small size? Mayroon po kasi akong nakita na Small size na pang 4kg-8kg. Any brand suggestion will be a big help. Thankies in advance.