EXTERNAL INSULIN PUMP,Cannula of the external insulin pump catheter. The cannula, generally composed of Teflon, is placed against the skin, enabling it to administer the insulin though the skin. The insulin pump is an electronic device enabling the administration of insulin through the skin continously, 24 hours a day. It contains a supply tank linked to a catheter. A needle-guide enables, during the insertion of the catheter to place correctly the cannula under the skin. This needle guide will later be removed.