Small-diameter fluorescent lamps, folded for compactness. Some feature a round adapter, allowing them to screw into common electrical sockets and making them ideal replacements for incandescent bulbs.
Newer fixtures allow CFLs to be plugged in directly without the round adapters.
Lamps that are thinner block less of their own light. Electronic ballasts represent a major step forward in energy-efficient lighting, offering savings in cost, energy, and pollution. Typically, electronic ballasts require bulbs designed for use with this type of ballast. Fixtures come in hundreds of shapes and sizes depending on their application. Some are designed to give architectural appeal and provide ambiance, and some are specially designed to minimize glare on computer screens and other working surfaces.