SmartKnitKIDSSeamless Sensitivity Socks - 3 Pack

My kid dethreads his socks - almost daily. if i’m gonna spend $30 on socks, i would like to know this can’t happen. is there a money back guarantee?

I am an adult woman size 8, would I be able to wear a child xlarge?

What is the lengh in inched of the size medium and large?

What size socks should I get for a 5-year-old boy?