Used, very good condition.

NO AC ADAPTER

Microsoft 1661 Dock Station for Mobile - Dock Stations for Mobile Phone Surface Cover, Tablet, Surface Pro 3, Surface Pro 4 

All the ports you need - with two high-definition video ports, a gigabit Ethernet port, four high-speed USB 3.0 ports and an audio output
Lightning fast with minimalist design - surface dock uses surface connect technology which enables high-speed transfer of video, audio and data over a single cable keeping your desk clutter-free
Easy setup - surface dock is quick and easy to set up, connect your peripherals to surface dock and then attach the magnetic surface connect cable to your device
The Surface Pro 1 and Surface Pro 2 are not compatible with this dock.