I ordered a few of these for my niece's 12th birthday to go under some of those loose fitting, off-the-shoulder tops I got her at Forever 21.  She wears long sleeves under them in the winter and tanks in the summer.  Forever 21 is an adult store, so their tanks, even size XS, are too low cut for a 12-year-old.  I ordered these tanks in size 10-12, and wish I had gone up a size.  I think they are more size 10 than size 12.  Still, my niece is nice and thin, so I think these will do for the summer.  Then she'll have to get other ones for next summer.  The next size up would have lasted her more than one summer.  I just hope these don't shrink, cause then they definitely won't fit.  Good basic colors.  Good price.  Free shipping if you are an Amazon Prime member.