[RAM]

I have a 1975 911S that I have begun to replace the front shocks. The inserts are Boge and I am at the point of installing the insert. I wanted to re-read the replacement process in "101 Projects for your Porcshe 911" when I stumbled on a particular paragraph. It says, "Check the ruber O-Ring at the top of the insert for damage and replace if necessary.". The insert I purchased had basicaly three parts, the insert, the nut that secures the insert in the shock tube and the nut that goes on top of the shaft (in the trunk). What rubber O-Ring are they talking about? I pulled the old insert out of the shock tube and I see and insert but I was told that this is not needed when replacing with pressurized inserts. What parts are needed when installing the insert?