Circular, reducing, cooker hood duct adapter

[curium]

hi i need to fit a cooker hood extractor which takes 120mm circular ducting to the existing 100mm circular ducting.

Where can I buy an adaptor to do this?

I would of preferred to enlarge the existing hole and use 120mm ducting but the cowboys who originally fitted it routed the ducting into the ceiling void and it exits the building from there so would be messy to get to.

Cheers for any help

 

[jj4091]

http://www.tlc-direct.co.uk/Main_Index/Ventilation_Index/Ducting_Round_1/index.html see adaptor at bottom of the page.