... 4.Temperature: Metal Dome: Dome is a piece of metal shrapnel, with the conductivity of the metal, it's used in circuit board PCB ... . It's widely used in mobile phones, walkie-talkie, MP3, MP4, GPS navigation systems, electronic dictionaries, digital photo frames, game consoles ... and other digital electronic products. We could produce a series of Dome according to customer's drawings. The button of MP3