It's called a Morgan Carb Tune and it comes from England somewhere. I have one and like it a lot -- no mercury to spill and a lot smaller too. I've taken it to a friend's house in the rear GIVI box.
It cost about $100 including S & H when I bought it over a year ago -- it's probably more now due to the dollar's devaluation.
Try searching for carb tune or carb tuner or Morgan carb tune and hopefully you'll find it.
It came to my house wihin a week of ordering over the internet.