A 46 cm (18-inch) Catheter Introducer (often called an introducer sheath or guide wire/stylet introducer) is an elongated medical device designed to facilitate the safe, precise placement of catheters into the vascular system or deep body cavities. The 46 cm measurement denotes the working length of the shaft, making it a medium-to-long reach instrument typically used in adult cardiovascular, radiological, or urological procedures.