2D bulbs are also known as butterfly bulbs, DD, or Double D lamps because of their distinctive shape. They are available in GR8 (2 pin) and GR10q (4 pin) varieties.
These 2D bulbs are most often used in utility lights, such as outdoor bulkhead fittings. They are also sometimes found in flush fitting bathroom lights where a lot of light is required from a low profile fitting.
