This O-ring seals the idle solenoid or idle jet holder (M8 threads) to the carburetor body on the primary side (only) of certain emission-controlled Weber 32/36 DGV/DGAV/DGEV carburetors. Sold individually.
Note: Not all DGAV and DGV carburetors use this size. The primary side of most DGV / DGAV / DGEV carburetors (and the secondary side of all DGV/DGAV/DGEV), have a smaller idle jet holder which has smaller M6 threads,
This same O-ring is also used on Weber DCOE and DCO/SP carburetors (all sizes, including Italian and Spanish made) to seal under the accelerator pump jet cover. Two are required per carburetor for this application.