This is a D-Sub25 3-circuit selector. It's a product with a D-Sub25 connector, which is no longer available on the market. I remember obtaining it as a modem selector, but it has been stored unused for nearly 30 years. I haven't tested its operation as I don't have a testing environment. There is no product information on the manufacturer's website. The outer box has some scratches, discoloration, stains, and deformation. Some of the styrofoam cushioning has deformed, possibly due to direct sunlight during storage. Please be aware of these factors, including the age of the item. The item will be packaged and shipped with the outer box wrapped in recycled materials. Frankly speaking, this is a product for enthusiasts. I cannot answer questions from those without the relevant knowledge.