Insulative rings (or paper) e.g. fibre paper, double sides pastern
2） PVC、trademarked tubes
3） Connections plates: stainless steel plates, nickel plates, nickel plating steel plates
4） Lead plates: stainless steel plates (easily tin soldered), nickel plates (strong spot welding)
5） Plugs
6） Protectors: thermal switches, polyswitches, current-limited resistances
7） Boxes and cases
8） Plastic shells