This kit was made as an upgrade retrofit (that extended the cost unit ability) of mechanical Veeder Root counters that were used in gasoline pumps to measure and display the cost of the gasoline delivered when gasoline was under 99¢/gallon. The kits include; an optics interrupter wheel, counting optics, model ECV5N3-1 5VDC/3AMP power supply and a Robco Industries R300 control board that is loaded with chips and parts.. Schematic available. All offers for these 500 kits will be considered as they must be sold. MF536 - 1 in stock