This is the Replacement Lock Nut Set from OS Engines.
Durbable steel construction.
Prevents the propeller from flying off even if the propeller
should slip or loosen due to detonation or knocking on
the large 2 or 4 stroke engines.
Replacement parts suitable for the BGX-1 3500-RN engine.
1 metal propeller washer
1 metal hex lock nut (sandwiched between prop washer and
1 metal hex expansion bolt (installed last inside the lock nut)