The Microsoft Surface Dock Model 1661 is a docking station specifically designed for Microsoft Surface laptops. With passive cooling capabilities, this black dock is compatible with various Microsoft models including the Surface Pro 3, Pro 4, Laptop Studio, and Go 3. It features ports for audio out, Ethernet, and USB 2.0, as well as magnetic and port expansion features for convenient use. Perfect for expanding the capabilities of your Microsoft Surface laptop, this dock provides a seamless and efficient connectivity solution.