This very rare item is a reproduction of the early TT bellmouth fitted to those early brass TT carburettors, where the carb body has a male thread. The item is chromed as per the original and very nicely made. Note - internal diameter at the point where the thread is reads 1.780" approx, using a digital vernier gauge
Update Jan 2016: Unfortunately we have now sold the last one of these and our supplier does not intend to make any more, which is a real shame. I have kept one back for myself - please email me if you need dimensions .. . or if enough interest I may consider making them in the future myself