5 Gallon Pail of Concentrated Hydrochloric/Muriatic Acid Concrete Cleaner Inner Tank: Food Grade SUS 304-2B, Outer Tank: Galvanized Steel 0.5 mm thickness Insulation: high pressure automatic polyurethane foaming layer, Density of 36 kg/m3, R-Value: 12.5 In Tank Coil: TU1 copper (Red Copper), thickness: 1mm, Length of Coil:66 ft Water Ports: 3/4" NPT, Coil Ports: 1/2" MPT, T/P Valve/Abode Rod/Drain Port: 3/4",