Upper Cover: High Temperature PBT/NiLong (UL94 V-0) or Spcc Lower Base: High Temperature Nilong /Bakelite(UL94 V-0) Actuating stem: High Temperature PBT (UL94 V-0) Chang Plate: Copper(Plating silver) Terminals: Brass/Copper(Plating silver) Sleeve: High Temperature NiLong (UL94 V-0) Spring: SWC/SUS304