Notre Dame Onesies Selling as a set! My son wore these in college football season! I feel they are both closer to 6-9 months, but the cotton onesie has a little more stretch. All hung to dry and in great condition! 1st Onesie (On Right with ND Irish on Front): 100% Cotton, Size 6 months-12 months 2nd Onesie (On Left Jersey with 00 ND on Front): 100% Polyester, Size 6 months - 9 months