... 35-40mm polyurethane2. Vacuum tubes: 58*1800mm/47*1500mm3. Single side collector:10,15,20,25,30pcs vacuum tubes4. Two ... -side collector: 50pcs ,60pcses vacuum tubes5. Bracket: 1.5mm galvanized ... circulation and automatic protection4.free pollution,energy saving:no social effects of pollution,no contamination,energy saving,green development5.outer chest:aluminium ...