J - 6 months ago, Verified purchaser
These are not made out of cotton (not even a little bit), which is clearly stated in the description. However, I didn't realize this until they showed up because I just assumed all kids' underwear would be made out of cotton. However, my son seems to like them, although I'm not sure if that is because of the comfort or the characters.
The size 6 fit my very skinny (but tall) 6.5 year old well.