1. Classification by function

A. Ordinary threaded inserts (Helicoil Free-Running Inserts) are marked "FR".

B. Helicoil Screw Lock Inserts are marked "SL".

2. Classification by wire thread insert material
A. Cr-Ni stainless steel material: Through the combination of strength and material, it is used under normal circumstances, in light structures, aluminum alloy structures, sea water, chlorine-containing liquids, and to increase corrosion resistance.
B. Copper alloy material: used when copper is required or when the threaded connection of rotation is often adjusted; used when it is required to be conductive or self-lubricating.
C. High-temperature alloy materials: heat-resistant for use when the temperature is between 500 and 750°C; used for aerospace assembly technology, aircraft engines, and internal combustion engine turbine compressors operating within 750°C.

3. Classification according to the type of internal thread formed
A. International standard ISO "M, MJ" series wire thread inserts. Thread series are marked "M", "MJ"; Spark plug thread thread inserts are in this series.
B. Unified thread "UN" series wire thread inserts (UNIFIED Thread Series). Coarse threads are marked "UNC", fine threads are marked "UNF", and ultra-fine threads are marked "UNEF".
C. The thread mark number of non-thread sealed pipe thread (British Standard Pipe Thread) is "G".

4. Classification according to the rotation direction of wire thread sleeves
A. Right-hand wire thread insert.
B. Left-hand wire thread insert.

5. Classification according to whether the wire thread sleeve has an installation handle or not
A. There is a steel wire thread insert with an installation handle.
B. Wire thread insert without installation handle.

6. Classification according to whether the wire thread sleeve is coated or not
A. Steel wire thread insert without surface treatment layer.
B. Steel wire thread inserts with surface treatment layer, such as: silver plating, cadmium plating, coloring, oxidation, etc.