An overlocker looper is a component of an overlocker machine (also known as a serger) that is responsible for creating the looped stitches that join the edges of fabric together and prevent fraying.
The overlocker looper is a small, pointed hook-shaped component that sits within the overlocker's looper mechanism. As the fabric is fed through the machine, the looper engages with the threads to create the looped stitches that bind the edges of the fabric together.