3 Piece Core Bowling Balls
These are balls that are made by filling the vast majority of a ball from the middle all the way to the shell with a basic filler material.
At the “top” of this filler material is a small pancake shaped dense weight block that provides some extra weight to compensate for the removal of material when finger holes are drilled around it.
These 3-piece bowling balls are commonly refereed to as having pancake cores that are not-dynamic in any way. They are basically symmetrical and provide little to no differential – meaning they don’t flare which causes hook potential to be very low.
In modern bowling only the most basic balls are made with three piece construction, plastic spare balls come to mind first.