A support stand includes a stand neck and a stand base. A step balloon protrudes from the delivery sleeve and provides a tapered surface for facilitating advancement through a body vessel. A cell gate capping layer may be formed on the cell gate electrode. The feeder includes a pump body with a through hole, one end of which is connectable to an ear adapter by a flexible tube and the other end of which is provided with an air pump device. The signal output circuit provides a DC voltage output to a display and the DC output voltage is representative of the position of the trim tab.