Float bowl nut seal for the Dellorto PHF carburetors.
Fits the 21 mm (spanner width) varieties of that special nut:
The inner diameter is some 20 mm, the outer diameter some 27 mm and it is around 1 mm thick.
This product is priced, and sold, as a single unit.
Required quantity per carburetor: 1
This is item number 73 in the drawing.
Dellorto Part Number: 2778