ERis a high-speed tool handle: ER is a tool handle with an ER collet, which is a collet type. This collet is 8 degrees on one side and is also a commonly used collet.
FMB metric: FMB is a face milling cutter handle, the front is used with a milling cutter head, also called a milling cutter disc or a flying cutter disc, and is mainly used for milling flat surfaces.
SK German standard: SK is a handle connection form, that is, a standard for connecting to the spindle, but there are also manufacturers that refer to the SK tool holder, which is a collet clamp tool type called SK, which is generally used more in high-speed machines.
