flush wooden door: Skeleton: hardwood or softwood Core: particle board, Germany core, honeycomb, fir, pine, etc Face: MDF, HDF, or plywood Veneer:Sapeli, beeth, birch, maple, ash, oak, cherry, teak, ebony,etc Size: Customized Fire door and reinforced door are available. Frame: MDF+face veneer Fir+ (MDF)+face veneer plywood+MDF+ face veneer)