... Hi-Tg FR-4 / Lead free Materials(RoHS Compliant)/CEM-3/CEM-1/AluminiumLayersingle layer,double layer ... no Open soldermask must cover all on both side, reject tin on pad Pad Open reject ... soldermask inside the hole on both side Solder Mask Thickness0.7mil,raised H≤0. ... time,+/-2%(tolerance) Certificate SGS,ISO,ROHS,UL, Welcome to visit WALBOND ! loudspeake and radiator PCB with UL standard