Notes: Air Gap Pipe. Appearance may be different than OE Pipe. Air space between Pipes acts as a Heat Insulator; If welded Assy, replace all Reqd parts.;Over 8500 G.V.W.R; Air Gap Pipe. Appearance may be different than OE Pipe. Air space between Pipes acts as a Heat Insulator; If welded Assy, replace all Reqd parts.