How does copper ammonia fiber compare with wool or acrylic?

It is a cellulose-based fiber with a soft, cool feel and a light sheen, closer to viscose or modal than to wool. It drapes well and does not itch, but it insulates less than wool and pills more easily than acrylic.

How should I choose a size?

The listed sizes are Asian sizes, which run one to two sizes smaller than US and European sizing. If you fall between two sizes, take the larger one, and check the size chart before ordering.

Is the sweater warm enough for winter?

It is a thick knit with a half-high collar, so it works as a mid-layer under a coat. On its own it is better for mild cold than for deep winter, since the fiber holds less warmth than wool.

Hand wash or use a gentle cycle in cold water and lay flat to dry. Copper ammonia fiber can shrink and lose shape with heat, so keep it out of a hot dryer and iron on low.