Single-lumen, long intestinal tube inserted through nose and allowed to travel to small intestine; uses balloon filled with mercury at tip to aid in passage through bowel. Tip is weighted and carried distally via peristalsis (thus not indicated in ileus). Device is useful in recurrent partial small bowel obstruction due to adhesions (esp. caused by radiation enteritis); also sometimes used in small bowel obstructions due to malignancy. FDA has recently banned tube secondary to risk of mercury poisoning.