Twin Set A124

You will have to order 2 different size 

One Adult size (Free Size)

Other according to your baby size (unisex)

Children's size chart C
Size, chest, height, weight
XS 16-22" 70-80 ст. 6-11 пп.
§ 23-24" 80-100 cm. 11-17 nn.
M 25-28" 100-120 cm. 18-24 kg.
L 29-32" 120-140 cm. 25-34 kg.
XL 33-34"140-160 cm. 34-39 kg.