80s Striped Thin Sweater or Boxy Top - not heavy or thick so may be best considered a top (somewhat like sweatshirt but thinner) Heathered Dark Gray into Black and White Stripe
No material content or other tags, feels like synthetic. No size tag - 25" long, 24" dropped shoulders, 44" free bust, 38" waist. Mannequin is 5'8" XS with 32" bust - this may fit S, M.
Flaw - material has very mild wear.

This item is sold from an excellent, highly rated vintage boutique.