The Voldyne Model 5000 Volumetric Breathing Exerciser is a reliable and durable breathing device designed to help improve lung function and capacity. With a volume of 5000 ml, this clear unit is easy to use and manufactured by Sherwood Medical in the United States. Although it does not come with a manufacturer warranty, this new old stock item is a valuable tool for personalizing your breathing exercises. Perfect for individuals looking to enhance their respiratory health, this volumetric breathing exerciser is a quality product that delivers on its promises.