6-Layer PCB with Gold Finger, Black Solder Mask, ENIG, Impedance Controlled, Vias Plugged with Solder Mask, RoHS Compliance. 6-Layer PCB,Gold Finger,Black Solder Mask,ENIG,Impedance Controlled,Vias Plugged with ... Peel Test (conductor peel strength) Impedance Test Ionic Contamination Test-------------------------------------------------------------------------------- 6-Layer PCB with Gold Finger