LED lights, as the smallest type of lighting, typically feature diameters not exceeding a quarter inch. One benefit of the lights' small size: Manufacturers can group LEDs in clusters to increase their usefulness.
A single LED may not offer considerable light output. Clustered together, however, a group of LEDs can put out an amount of light comparable to most other types of household light bulbs on the market. A 12-watt LED cluster bulb, for example, offers output similar to a 60-watt incandescent bulb, depending on the brand, and costs about $40 as of 2010.
The high cost of LED technology may explain, in part, why manufacturers haven't made more progress toward producing single LEDs that burn brighter while still offering the same energy efficiency.