Sock-weight version: small preemie
US C/D crochet hook
yarn:
white - 1 ounce
yellow - a few yards
blue - a few yards
gauge: 11 dc = 5 cm (2”)

DK version: medium/large preemie
US E/F crochet hook
yarn:
white - 1 ounce
yellow - a few yards
blue - a few yards
gauge: 9 dc = 5 cm (2”)
worsted weight (newborn):

Worsted weight version: newborn
US F/G crochet hook
yarn:
white - 1 ounce
yellow - a few yards
blue - a few yards
gauge: 6.5 dc = 5 cm (2”)

all sizes: three 1/2” - 3/4” buttons