What does a CFL light bulb look like?

Compact fluorescent light bulbs (or CFLs) are identified by the white glass tube spiralling up from the base of the bulb that houses a tiny electronic ballast. This design has since been modified by placing a secondary glass housing around the spiral fluorescent tube to make it more appealing.

Compact fluorescent light bulbs are used to replace the standard household A19 light bulb with a more energy efficient solution. This category of light bulbs has since grown to include flood lights (recessed can lighting), globe lights (bathroom fixtures), and variations of outdoor lighting. While the appearance of CFLs has changed the spiral versions are still available at a lower cost to consumers.