These brand new Triumph TT motorcycle exhaust pipes are 1-3/4" OD throughout and fit over the exhaust head spigots on your 650cc pre unit or 650cc unit Triumph motorcycle. These are really nice in that they have threaded bungs welded on (before the beautiful chrome of course!) so you can fabricate mounts easily. Both pipes tuck underneath frame, great for your chopper, cafe or race bike. Made In England.