I always thought this was a sweater, but Madewell says it is a "fancy lightweight terry" top. This has been washed on delicate cycle, inside out, & air dried. From Madewell: Cozy-meets-pretty in this party-ready top. Made of a fancy-ish lightweight terry, it has a deep v-neckline, puff sleeves and a thick banded bottom with buttons down the front. Please note: this style runs large, so we recommend ordering a size smaller than your normal size. 100% Cotton. Machine wash.