Long idle jet as found in early Dellorto DHLA series carburettors like used by Alfa Romeo and Lotus.
Available in sizes 48 - 52.
Required number per carburettor: 2
This is item # 6 in the drawing.
Long Idle Jet for early Dellorto DHLA
Dellorto Carburettors - Jets - Chokes - Emulsion Tubes - Service Kits