CycleOps Powertap SL+ Wheel/Computer

Description

First of all, I am not familiar with the CycleOps stuff.  I bought this setup from a guy, who also knew nothing about it. After looking at all the documentation, here's what I have:
-CycleOps Powertap SL+ Ant rear road wheel, carbon hub shell, Shimano/SRAM 9/10 maybe 11-speed (not sure about that), 32 stainless spokes, with what I think is a factory laced Aerohead semi-aero rim.  Don't hold me to that.  It is a very high quality, pretty light wheel with minimal miles, beautiful gold rim, spins perfectly and is dead true.  All the electronics inside the hub are excellent. No skewer.
-All the pictured electronics, with computer head unit that fires right up with good batteries.
-All documentation, including two computer discs (remember those?). A little Cordura pouch designed to carry everything except the wheel itself.
I thought I had a ready-to-go setup BUT turns out it was missing the little sending unit that is mounted on the chainstay to receive data from the hub and relay it to the computer.  I think it might be called a Shark's Fin, but, again, don't hold me to that.  From what I can glean from the Internet, that part is absolutely unavailable, so I have a great unit that I can't use.  I used the wheel a few times, and it is a very solid, medium weight wheel.
So, if you have access to the part that I am missing, you can have a PowerTap wheel setup for less than half price.
Shipping quote is CONUS only.