Don't quote me because I've not actually seen one, but I'm pretty sure it's a pretty similar gadget to a Power Commander. It's used to download and/or tweak the tunes in the bike's engine management system.
It's a program that you load on your computer, you use their cable to connect to the bike's OBDIII cable (under seat next to battery) and once you are provided with a software key by Tuneboy, you are able to upload tunes just as the Triumph tool does. Good product, horrible or totally nonexistent support and can be a pain in the ass to set up initially.
And, obviously, I didn't realise Tuneboy was software. That's pretty cool if you're into tweaking. Again, I thought it was just another fuel management type gadget like the PC or V&H Fuel Pak.
It all makes sense now, however. Scot in Exile has told me more than once I could use his "cable" anytime when tunes come up in conversation. I assumed he was changing the subject and always just take a few steps back, hold my hand up and politely say "No thanks, I'm not that kind of guy". I guess he wasn't trying to change the subject after all.
No.. alas, I'm a lowly PC-III user... I probably should spring for TuneBoy though as you can do so much more with it. I know it would have saved some cash when I had to replace my TPS...
Think long and hard before you make the jump, once you do you cannot turn back
All Tuneboy is - is a cable a special cable but still a cable with a key to let it play around with your bikes ECU
The Tuneboy web site has screen shots of a number of parameters that are a small part of the total software package. You can download the entire software package, no charge, to see all that is possible. The cable alone is useless without the software, so it's not just a cable. But you will have to be able to park your Rocket up along side a computer.
A word from experienc: Youre quite apt to run into snags from time to time; everything in not cut and dry. And communications with Tuneboy, Wayne, to iron out the wrinkles can be very disappointing. Being patient with uploads is key.
Sometimes I kick my self for the expenditure, then I consider the diagnostics side of the software package; then I don't hurt so much.