... carbon steel sprayed with plastic housing·Can built-in air compressor, can feed with oxygen.·With built-in ceramic ozone ... life time·Easyoperate for system, it can add ORP on control for water PH·Smallin size, adjustable ozone range: 20%-- ... over voltage, water protection device, for ensuring ozonemachine running safetyControl panel:Ozone output adjuster, Flow meter, ORP (Choose),Pressure regulator, ...