This product, with UV sterilization function, can ensure the fish tank clear and bright effectively. It’s very simple for use and great for effects. Features: High quality filament for high performance and energy-saving. Adopt quartz glass tube for high transmission of ultraviolet ray. Powerful suction cups for adjusting position freely. Safe water-proof design for totally submersible use. Suitable for controlling malignant bacteria in aquarium and fish tank. Specifications: Body Material: Quartz Glass Plug: EU Plug Voltage: AC 220-240V Frequency: 50/60HZ Wattage: 5W / 7W / 9W / 11W / 13W(Optional) Power Cable Length: Approx. 200cm / 78.7in Tube Diameter: 19mm / 0.75in Lamp body Length: 5W: 195mm / 7.67in 7W: 200mm / 7.87in 9W: 225mm / 8.86in 11W: 245mm / 9.64in 13W: 245mm / 9.64in Package Size: 28.8 * 8 * 4.5cm / 11.34 * 3.15 * 1.77in Package Weight: 5W: 258g; 7W: 259g; 9W: 245g; 11W: 271g; 13W: 271g Notice: 1. The sterilizer should be placed in filter-tank, can’t put it in the fish