Ureteral Access Sheath is a medical device used in urology to facilitate the insertion of instruments, such as ureteroscopes, into the ureter and kidney during minimally invasive procedures. It is a hollow, flexible tube that provides a stable pathway, protecting the ureter from trauma and improving the efficiency of procedures like stone removal, tumor biopsy, or stricture treatment. Ureteral access sheaths are essential tools in modern endourology, enhancing both patient safety and procedural success.