06-13 HARLEY FLHX2: Mustang Wide Recessed Rear Seat (Studded) The Mustang wide rear seat has a slightly recessed front end to allow clearance when being installed behind a Mustang solo with the built-in driver backrest.Features Mustang's unique internal steel support wings to keep the entire width of the molded foam Notes: Will NOT fit with handrail. Mustang Solo Mounting Nuts are needed in order to install the passenger seats on all 1999 - 2013 FL Touring models. The hardware is needed to convert one-piece seats to two-piece seats.