I'm 5'4" 120 lbs and normally I'd get a Small, but I got the size Medium based on other reviews. I'm glad I did because these tank tops are still skin tight on me.

They are made of a thin stretchy knit, and work great for layering. The built in "bra" looks like a regular shelf bra, but it's as supportive as a tight tshirt. In other words, zero support. I'm very small chested and these tank tops didn't even feel tight in the chest area.

I'm okay with this, but part of why I got these was to use instead of a bra (like I can do with most tank tops with shelf bra). I'll give them 3 stars for looking cute, but being misleading about these tanks acting as a bra in any way.