Attached are a few photos of the Protac backrest for the EN500.
Here are pictures of the backrest itself.
Installation is a real no brainer. Here is a picture of the really complicated instructions packed with the backrest:
Really hard to understand, huh??
Just remove the bolt on each side of the chrome strut closest to the coil spring as indicated by the red arrow.
Attach the bracket so that the twisted end with the plastic protecter rests on top of the chrome strut and tighten. (To protect the chrome strut I placed a piece of rubber between the brackets and the chrome strut. I used a piece of inner tub patching cut to the shape of the bracket, then peeled off the white linen and stuck it to the bracket.)
Then slip the back rest into place. There are 2 holes in each bracket so there is some room to adjust the position horizontally, and as mentioned in the instructions a wedge can be used to adjust the vertical angle.
I find the ability to just slip the backrest in and out of the brackets very convenient - easy to instal and remove when not wanted.
Here is the bike ready to go.