Ah, the power of Amazon...
The GS-Wing is an add-on to the older SENSAR - in grey.
http://www.amazon.com/Winegard-GS-WI.../dp/B002DPTQXW
Says NOT INTENDED FOR RV USE
The RV-Wing, also called the "Wingman" is very similar in white - but with 2 less holes in the base/mount plate:
http://www.amazon.com/Winegard-RV-WI...KQ68X9RQ7PEMTR
Both need/use an old SENSAR "Batwing" and are not needed if the RV has the Sensar IV or newer.
The grey one is less $$ and maybe has weaker mounts or no feet for the stowed position(?)
A whole new SENSAR IV head for a RV in white is only slightly more:
http://www.amazon.com/Winegard-RVW-2.../dp/B003ZOH63W
I added the white one to our SENSAR III and noticed an immediate improvement in the number of signals that could be received.
Safe travels