[Jayk]

You sure that description is right ?
The left transponder is the purcy and will only work on tracks with the new rc4 decoders and not many clubs will use it yet as they know there members will have to upgrade to it, some clubs offer discount on mass trade ins etc..
The right one is the older amb and will still have a good few years left.
The harry hybrid works with them all and looks like the purcy but with white writing etched on it (purcy has black transponder personal id)
The mrt ptx black transponders are not a mylaps product so they wont support it but a new one is supposed to be rc4 compatible, i think mylaps dont want people cloning em, mylaps could possibly stop em working ? But they are more affordable.
I just got the older amb one at a good price i think it will last a while longer.