Recently got a 2012 cannondale trail sl 3 and wanted to get a different saddle. This is my first mtb. Im looking at the selle italia slr xc flow and noticed it has a monorail and my cannondale is dual. Do I have to buy something additional if I choose to go with slr xc or does it come with a bracket? Again I'm new and so I apologize if this is a dumb question haha.