3* years warranty. Special steel guard lining with epoxy marine tripple coated inner tank. Special three layer glass tube. Special stand and structure without welding. Pressurize system available. 24 hours hot water any time any where. Wide range with maximum features. High efficiency selectively coated copper absorbers. Sturdy, pure polyester powder coated collector box. Ultrasonic welded fin-tube assembly. Inner hot water storage tank made of food grade stainless steel of 304 grade.