0.4 mm thickness pcb, via on pad pcb, hdi pcb, thin 4 layer pcb Layer count: 4 HDI PCBMaterial: FR4 , 0.4mm, TG 180, 1 OZ for all layerMinimum tack: 3.6milMinimum space(gap): 3.6milMinimum hole: 0.10mmSurface finished: ENIGPanel size: 290*268mm/48upCharacteristics: high density interconnect PCB,via on pad(plug with resin,and plate copper flat), high TG, thin thickness for multilayer www.hiquality-pcb.com