It's made of a thin wetsuit-like material and is lightweight, with a beautiful shape! I bought it without trying it on, and after cutting the tags and wearing it, the size didn't quite fit, so I'm sadly putting it up for sale. Only tried on at home. XS, but it's about a Japanese size S to M! Beige Polo Ralph Lauren XS size T-shirt - Brand: Polo Ralph Lauren - Size: XS - Color: Beige with brown embroidery