... / Aluminum die cast for high-end microphone cover with double plating Manufacture Process1) Mould/Tooling analysis, design ... , polishing, cleaning, finishing, passivation, including infiltration & double plating6) Full Inspection7) PackingProduct Description1) Material: Aluminum alloy2 ... Tolerance: +/- 0.0005inch, also accord with GB6414 Aluminum die cast for microphone part with double plating