MEDIUM size. I guess looking at the pic I expected it to be like a stiff cotton material like a actual collard shirt but I didn't look at the material in description also lol. I would have kept anyway but like a few other of the rompers I've tried it was all Torso and no room for butt and thighs and i'm only 4'11, 140 lbs, chest C32. it was like wearing a bodysuit that just barely covered my butt and pelvic area. I definitely would've kept if it was longer because it was comfortable and still looked classy aside from the length.