Size of cold air ducting trumpet from fog

[UFO Yellow]

Hi,

I'm gonna be fitting a jetex filter at the weekend and I wanna fit a a cold air ducting hose from the fog light.



I searched to see if there were any threads with any info on what size of trumpet to get to fit the fog light hole but couldn't find anything.

Anyone got any ideas?

 

[Murdered LCR]

80mm ish eBay that's where I got mine

 

[UFO Yellow]

Cheers, I'll have a look