LJXH Heating Element Foldback Type Water Solar Heater with ScrewIn 1 INCH BSP Thread 240v 1kw/2kw/2/3kw/3/4/5 Product Name: Water Heater ElementTube Length: 180mm/210mm/250mm/270mm/290mm/370mmTube Diameter: 8mmThread Size: 1" BSPVoltage: 240VWattage: 4/5/6 Material: 304 Stainless SteelThread Material: 304 Stainless Steel Package Contents: According to what you choosed Please Note: Because the heating twine contained within the heater tube is made of OCr25A15 which is Magnetic, it's common that the element could be adsorbed through magnet. The tube floor materials is made from stainless steel 304. If you're care about it, please do not make order.