Thule tow bar bike carrier 3 VC 927. This is great for 3 bikes or 2 or even 1! All 3 bike arms included. 2 keys included - to lock onto the tow bar and to secure bikes when on the rack. Thule are the best out there.
Does have capacity to add a forth bike but this rack does not currently have that feature. If if the future you want to too, you can add on.