The beautiful designed power adapter for the iBook Clamshell has a Plug with 9,5mm external diameter. The Apple model number is M7332.
If you plan to buy a replacement you have to check the appearance of the plug because the identical power adapter with a smaller and darker plug was used for the first white iBook and PowerBook G4 Titanium models. This one is incompatible with the iBook Clamshell.
On the right you see the M7332 power adapter for the Clamshell iBook.
The two plugs from a different perspective.
Below the iBook Clamshell power adapter.