... with immersion gold 3.1.6mm pcb electronic 4.Red oiled double board PCB boardWe are a professional ... short lead time .We choose the best material for all our products ,and the quality of our products is ... ,Immersion Tin ,Immersion Silver ,OSP etc,Solder mask :Green , Red , White ,Yellow ,Black ,Blue . We sincerely hope to establish ... and hope to your most reliable partner in the near red pcb board