In the box are the instructions and a longer leather grab strap. Installation was fairly easy -- the part that took the longest was removing the old grab strap and replacing it with the new one.
From this angle you can see how much wider the Sundowner passenger pillion is from the stock seat. It measures 14" at the widest point, hence the need for a longer grab strap.
Stock FLHX seat
Ride Result - for the rider, I don't think you will feel any difference in terms of comfort between the stock and the Sundowner seat... the Sundowner is a bit deeper, so you might find a little bit of back support but according to my passenger, it makes a world of difference!