Do I need to wear something under it?

Yes. The lace is sheer and unlined, so plan on a camisole, tank or bralette in a matching or contrasting tone. A nude underlayer keeps the lace pattern readable.

How does the sizing run?

The listed sizes are Asian sizing, which typically runs one to two sizes smaller than US and European sizes. Measure your bust and compare it to the size chart rather than ordering your usual letter size.

Can it be worn open like a cardigan?

Yes. The button front and cardigan cut let you wear it open over a tank or dress. Worn closed and tucked in, it reads as a blouse.

How should I wash polyester lace?

Hand wash in cold water or use a mesh laundry bag on a delicate cycle, then air dry. Skip the dryer, since heat can distort the lace and loosen the buttons.

Is it warm enough for winter?

No. It is a single layer of thin polyester lace with no lining. It works as a mid-layer under a jacket or sweater in cold weather, not as outerwear on its own.