Holder for the idle (or progression) jet for the Weber DCNF series carburetor.
This is the current production version of this idle jet holder that measures some 13 mm in overall length.
Early versions of these carburetors used a different holder that measured 17 mm in overall length.
That old version can be found HERE.
Required quantity per carburettor: 2
This is item number 27 in the drawing.