LOTS of stretch! I've been eyeing this piece for some time waiting for it to come back in stock and 1 XS dropped. I'm usually a Med, size 8 bottoms and Med top at 155 lbs. I took a chance with the XS and because of the stretch it worked out fine. It is a slight see through but to me it just makes it sexy. Its not suffocating either, you know some things can be TOOO tight, this isn't.