Exel International’s butterfly infusion set, or scalp vein set has a 21g x 3/4in. thin wall stainless steel cannula, that is siliconized for easy insertion. It has a 12in. tube with flexible wings that hold the needle in position and helps to prevent inadvertent pull out. This infusion set has a deep green-colored hub for easy identification. Each scalp vein set in this box is latex free and individually packaged.