Product Model: Blue Solder Mask Rigid-Flex PCB Material: FR-4 + PI composite substrate Layer Structure: 4 layers Solder Mask: Blue / White Finished Thickness: 0.6mm Copper Thickness: 0.025mm Surface Finish: Immersion surface treatment Min. Trace / Space: 0.1mm / 0.1mm Application: Communication and digital rigid-flex electronic devices