Used in 2 locations on the carb. Quite common to be missing from the Idle Jet and may not make much difference as some of the MB literature does not show it. Other Literature does. All the literature shows it as a requirement for the Pump Nozzles (Located just above the choke housing.) Lubricate these slightly prior to installing them as they tend to tear when installed dry. 4 Required per Carb. New Manufacture, German. No Longer Available from MB. Included in 0000715301RK - Complete Carb Rebuild Kit, and ZE32GK Carb Gasket kit.