Color classification: brown red purple green black orange pink sky blue
Reference height: 

XS (chest measurement 28-33cm, 1-3kg recommended) choose 

S number (chest measurement 36-41cm, 3-5kg recommended) choose 

M number (chest measurement 41-48cm, 4-6kg recommended) choose 

L (chest measurement 48 -58cm, recommended 7-13kg) choose 

XL size (chest circumference 51-74cm, recommended 14-25kg)