I saw these in photos of 911 2.5 ST 911 230 1687 post restoration and wondered if anyone knew where to source these clip on mesh filters? Presumably they have a flexible collar to stretch over the widest part of the trumpet and then contract again to give a good fit? I have looked on eBay and found similar ones for Weber carbs up to 70mm diameter but the Porsche Delrin trumpets are 84.75mm outside diameter...

911 230 1687 (7).jpg911 230 1687 (12).jpg
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Any ideas @gled49?

Thanks!