FSK,vapor barrier,fire/sound retardant,,used for metal building,HVAC system,industry packing,equipment refrigeration. FSK Facing,Heat Insulation,Vapor Barrier,Fire/sound Retardant,,used for metal building,HVAC system,industry packing,equipment refrigeration.Material:a.foilb.2-way or 3-way fiberglassc.polyethylened.kraft paper FSK Facing For Metal Building