Final answer:
Dean Kamen's Slingshot is a water purification device, but the specific annual purification capacity is not provided in the reference texts. However, related technologies indicate potential purification capabilities in the range of thousands to millions of liters annually.
Step-by-step explanation:
Dean Kamen's Slingshot invention is a water purification device that can transform polluted water or even seawater into drinkable water. While the specific production capacity of the Slingshot itself is not detailed in the provided texts, similar technologies like large-scale desalinization plants and small hand-operated reverse osmosis units are discussed. For example, small reverse osmosis units can produce approximately 5 liters of freshwater per hour. If we were to extrapolate from these figures, we might infer that the Slingshot could potentially purify thousands or even millions of liters per year, given its application in broader initiatives and its capacity to support a significant number of people.