This product, with UV sterilization function, can keep the fish tank clean and bright effectively. It's very simple for use and with great effects. Features: High quality filament for high performance and energy-saving. Adopt explosion proof quartz tube for high transmission of ultraviolet ray. Powerful suction cups for adjusting position freely. Safe water-proof design for totally submersible use. Independent power switch is great for safer use. Suitable for controlling malignant bacteria in aquarium and fish tank. Specifications: Wattage: 5W / 7W / 9W / 11W / 13W (Optional) Voltage: EU: AC220-240V; US: AC110-120V Body Material: Quartz Cable Length: Approx. 150cm / 59in *Product Size(D * L): 5W/7W: 20 * 177mm / 0.8 * 6.97in 9W: 20 * 220mm / 0.8 * 8.66in 11W/13W: 20 * 240mm / 0.8 * 9.45in Product Weight: 5W/7W: 125g; 9W: 134g; 11W/13W: 144g *Package Size(L * W * H) 5W/7W: 23 * 7.5 * 4cm / 9.1 * 2.95 * 1.57in 9W: 26 * 7.5 * 4cm / 10.2 * 2.95 * 1.57in 11W/13W: 28 * 7.5 * 4cm / 11 * 2.95 * 1.57in Package Weight: 5W/7W: 168g; 9W: 182g; 11W/13W: 190g Notice: 1. The sterilizer should be placed in filter tank, can't put it in the fish tank directly. 2. The product is for submersible use. 3. In use process, please cut off the power supply and stop using immediately if the lamp enters water. 4. The ultraviolet radiation will cause direct harm to human skin and eyes, please don't expose to use. Usage Suggestion: Please choose the suitable lamp according to the size of your fish tank and filter-tank. 3-4 times for a week, do not use it exceeds 2 hours per day; please according to the actual situation. Package List: 1 * Aquarium UV Sterilizer Lamp 2 * Suction Cups