Lighbulbs: After CFLs
"...Turned off, a Switch bulb looks like an incandescent from the future. It's got the same pear shape as a standard bulb, but it's divided into two sections. The bottom half is composed of a wavy metallic structure that looks like the wings of a badminton birdie. Above that is a thick glass orb filled with a cooling agent and a bank of LEDs, which are semiconductors that produce light. Because LEDs use a fraction of the energy required to light up the filament in an incandescent bulb, they're seen as the next great advance in light bulbs. LEDs have advantages over CFLs, too—they don't contain dangerous chemicals, and they can be used in lamps with dimmer switches..." - Slate