Timing Retarder Eliminator. It is supposed to improve throttle response and remove the top speed limiter. I haven't noticed an improvement in throttle response and don't know if the top speed has increased since my speedo won't display a number higher than 186 and I don't have a GPS.
There are plenty of people who make the TRE. Ivan's is probably the most well known.
http://www.ivansperformanceproducts.com/tre.htm
Here is the one I have:
http://www.motorcycleradar.com/products_pg5_5.htm
This one is more expensive but is "smart" and is also a much cleaner looking unit than the Ivan's.
It isn't hard to make your own either. You can do that for a couple dollars. There are plenty of how to resources on the net.