... fireproof and waterproof 2. Light weight, heat insulation 3. Installation is easy Rockwool wall sandwich panel:Steel Thickness: 0.35~0.6 mmPanel ... ) upper layer is steel sheet,(2) the inner layer is rock wool sandwich,(3) the bottom layer is also steel sheetRockwool density: 120 ... the large size factory buildings, storages, exhibition halls, gymnasiums ,etc Insulation rock wool sandwich panel