The bushing goes on the outside of the 1.5 inch tower pipe. There is no slip ring. The Rover operates off a wire tension system. Of course, a Windy Nation slip ring can be added for an additional cost. We have found that even after several months of operation, tower wires will rarely become twisted. You can simply install a 3-prong (extension cord style) male/female plug at the bottom of the tower. Every 3-4 months, you can disconnect the plug, unravel the wire if there are any twists, and plug it back in .... or you can purchase a slip ring if you do not want to deal with that.