Light weight warmth!
I bought this suit for my 3 month old in the 6-12 month size . . . even though he is 11lbs and an average size baby, because we cloth diaper everything needs to be sized up so I thought I go for the 6-12 month size to get extra life out of these as I read Engels run small. It is a bit big in the arm length but once you roll the sleeves with his big fluffy bum it fits nicely and should last all winter long and into the spring! But if you want a perfect fit I would have ordered the 3-6 month size for my 3 month old. The fabric is lovely and soft, feels light but warm and will be perfect as an extra layer in our chilly house without overheating. I love woolies for babies!