... material, 1oz copper, board T0.2mm2. Immersion gold3. Application moblile phone keyboard with competitive price5. Certificate: ROHS, UL, ISO9001-2000, ... pcb, 48 hours for 4L pcb, 72 hours for 6L and 8L pcb, 120 hours for 10L or more high pcb at the soonest. mobile phone ... keyboard 4 layer pcb board China