Brother are you asking about the piece on the bottom of the rod? Flat head Briggs engines do not have a oil pump, etc. so the engine has a splash oil system. The piece on the bottom of the rod is called an oil dipper, while the engine is running the oil dipper splashes the oil that is in the bottom of the crank case around inside the engine. Factory oil dippers are a piece of sheet metal that bolts to the bottom of the connecting rod however they are known to break at over 3600 rpm so the racing rods like this billet rod have the oil dipper machined in to the rod cap as we run the race engines between 6000 and 10,000 rpm.