Here is the solution if you need to have a bushing in your exhaust system. It can be used as a "Babushka" sytem one in the other or single. Each bushing is slotted that it can be squeezed for at least an extra Millimeter.
Average measurements are (app.):
1. 38/40mm
2. 40/42mm
3. 42/45mm
Wallsizes are 1,2mm. Rostprotected steel, sold as a set of 3.