PL-Type Lamps come in a number of different base types including G-23, GX-23, GX23-2, G24-d2, G24-d3, G24-q1, G24-q2, and G24- q3. These base types include 2-pin and 4-pin connectors.
PL CFL's are long lasting energy saving light bulbs which are much more efficient than incandescent and halogen light bulbs. However, PL bulbs do require fittings with the appropriate lamp holder and appropriate ballast. 4 pin bulbs can also be dimmed when operated on an electronic dimmable ballast.