Pen Plax CC15 Lux 15W PPX Crystal Bulb MEASUREMENTS AND POWER: the light bulb is 6 inches long, has 15 watts of power, and is standard with 120 volts. BRIGHTENS UP YOUR TANK: with a clear lightbulb, your tank will light up in a realistic light GOOD FOR YOUR PLANTS: lights are always needed for plant growth, so this lightbulb will become an important part of your tank SAFE AND LONG LASTING: scientifically designed to last longer, plus, it has a non-rust aluminum base making it safe for your pets.