... black, blue, white, yellow, purple, and matt, etc.Solder mask hardness: 6HLegend/Silk screen Color: white, yellow, black, etc ... , Immersion silver, etc.Other Technology: Gold finger, peelable mask, Non-across blind/buried vias, characteristic impedance control, Rigid ... probe test/fixture test, impedance test, solderability test, thermal shock test, hole resistance test, and micro metallographic section ...