I bought this to use in my XR9 Pro tranny, but it needs a newer version of Open Tx than the XR9 Pro will run. It uses the JR size module socket. I had it from a member of the BMFA who had bought a Radiomaster TX16S instead (like me)
£20 posted or you can fetch it from Walsall. near J10 M6 or the end of M6 Toll.
The last price I found for these was £49.99