The Five Metal Cooley Coronary Dilator with a 5mm Shaft is a specialized cardiovascular surgical instrument designed to dilate the coronary arteries during heart surgery. The 5mm shaft provides the ideal balance of strength and flexibility, allowing the surgeon to gently and precisely dilate the arteries without causing trauma to the surrounding tissues. It is typically used in coronary artery procedures to assist in widening the vessel for improved blood flow or to facilitate the insertion of grafts