With the average expected life of many standard bulbs at 750-1000 hours, many people were frustrated with having to change bulbs all the time. Another problem was the high cost of energy used in home and office lighting. These two different challenges lead designers at Osram Sylvania, Philips, TCP, GE (General Electric), and others to develop an alternative bulb that would solve both issues. Linear fluorescent lighting was one answer, but the need for bulbs that fit into small light fixtures was quickly realized.

Smaller versions of fluorescent bulbs were created, to accomplish this. They became known as compact fluorescent bulbs or CFLﾒs. Because of the need for ballasts in order to make them light up, these bulbs did not fit into normal light sockets. The 2-Pin CFL bulb became a wonderful alternative to standard incandescent light fixtures. Due to the higher initial cost, however, these bulbs remained mainly in commercial lighting applications.

Two-Pin CFL bulbs, like all fluorescents, are powered by ballasts. Ballasts are heavy devices mounted inside of fluorescent light fixtures and connected by wires to the sockets. The sockets for these bulbs are designed to last longer than the bulb itself, therefore the bulb was removable from the base and several bulbs could be used before the base would expire. This helped to keep the cost of the bulbs down.

2-Pin CFL light bulbs are available from all major lighting manufacturers: Osram Sylvania, GE (General Electric), Philips, and Westinghouse. They come in single tube, twin tube, and triple tube varieties.

The GE (General Electric) line is referred to as Biax. Specifically, Plug-In 2-Pin Low Wattage Biax. The description lists the wattage, followed by SPX (single tube), followed by the color temperature (discussed below). For example, F13BX/SPX41/840, F5BX/SPX27/827, F7BXSPX35/835, etc.

The Philips line is referred to as PL-S. The next information listed on the product description is the wattage, followed by the color temperature (discussed below). For example, PL-S 7W/27, PL-S 7W/41, PL-S 13W/30, etc.

The Osram Sylvania line is referred to as Dulux (doo-lucks). The letter after the word Dulux refers to the style of bulb. For example, Dulux S refers to a single tube. Dulux D refers to a twin tube. Dulux T refers to a triple tube.

Manufacturers knew that people would need more color choices with fluorescent bulbs than just warm white and cool white. You can find color temperatures of 2700K or 27K (very warm white), 3000K or 30K (warm white), 3500K or 35K (warm/cool blend), 4100K or 41K (cool white), and 5000K or 50K (pure white).