Yeah I have the Corbin and love the back rest, I went with the smallest backrest so it is easier to get past getting on and off, I had a Utopia one before which I sold to
@1olbull and it was great with plenty of adjustment it will fit if you have the seperate rider and pillion seats here is a link
http://www.utpr.com/rocket.html other wise you can get the triumph classic one piece seat and backrest if stil available, I also just noticed that utopia now make a backrest to fit the classic one piece seat as well