... Controlled, Vias Plugged with Solder Mask. 4-Layer PCB,Gold Finger,Red Solder Mask,HASL,Impedance Controlled,Vias ... warp & twist check) Dimensional Inspection (finished hole sizes, pcb profiles, etc) MicrosectionSolderability Test (245±5ºC; 3-5 ... ) Impedance Test Ionic Contamination Test-------------------------------------------------------------------------------- 4-Layer PCB with Gold Finger