The 4 pin compact fluorescent bulbs range in wattage from 13 to 55 watts; the base of the bulb has four pins to make it more versatile with a wide variety of light fixtures. Light output ranges from 700 to 3,500 lumens, while using up to 70% less energy than incandescent light bulbs. They are common in office settings, schools and churches. The Spiral CFL is a design with fluorescent tubes shaped in a spiral. They are excellent with light distribution and suitable for lamps and small fixtures. The spiral compact fluorescent bulb is ideal for reading lamps and is 1 inch in diameter. A single twin tube consists of a bulb with two fluorescent light tubes and has a high light output but uses very little space. The color cathode CFL, which uses no filament to generate light, is 3 mm in diameter, making it great for dimmers and photo scanners and has a 50,000 hour life. These light bulbs come in a variety of colors such as frosted, cool white, daylight, green, red, yellow, and pink.