Scalp vein set, also called a butterfly needle or winged infusion set, is a sterile medical device used for venipuncture, such as drawing blood or administering intravenous (IV) therapy. It consists of a small needle with flexible "wings" for gripping, a transparent tube, and a connector that attaches to other medical equipment. These sets are often used in patients with difficult venous access, such as infants, children, and the elderly.