This product, with UV sterilization function, can ensure the fish tank clear and bright effectively. It is very simple to use and great for effects. Features: High quality filament for high performance and energy saving. Adopt quartz glass tube for high transmittance of ultraviolet rays. Powerful suction cups for adjusting the position freely. design waterproof safe for fully submersible use. suitable for controlling malignant bacteria in aquarium and fish tank. Specifications: Body material: Quartz glass Plug: shuffle MP3 Voltage: AC 220-240V Frequency: 50/60HZ Power: 5W/7W/9W/11W/13W(Optional) Power cable length: approx. 200cm / 78.7in Tube diameter: 19mm / 0.75in Housing length: 5W: 165mm / 6.5in 7W: 185mm / 7.3in 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: 235g; 7W: 235g; 9W: 245g; 11W: 271g; 13W: 271g Notice: 1. The sterilizer should be placed in the filter tank, it can not put into the fish tank directly. 2. The product is for submersible use. 3. In the process of using, please cut off the power supply and stop using immediately if the lamp enters the water. 4. Ultraviolet radiation will cause direct harm to human skin and eyes, please do not expose to use. Suggestion for use: Please choose the appropriate lamp according to the size of your aquarium and filter tank. 3-4 times for a week and 10 minutes-1 hour each time. If there are large number of algae in the aquarium or sick fish in the tank, can use this sterilizer 1-2 hours per day, but do not exceed 2 hours. When the symptom becomes better, please return to normal use. Package List : 1 * UV Light Sterilizer