An E12 bulb refers to a specific base type used on a light bulb, with the E standing for Edison. The two digits after the letter "E" indicate the diameter of the screw base, in millimeters - 12 millimeters, or approximately half an inch. E12 bulbs are commonly used for decorative, candelabra light bulbs, as they have a smaller screw base that allows for more compact and decorative form factors in elaborate ceiling and chandelier lighting fixtures. The wattage ratings for incandescent E12 bulbs are typically 40W or less, and they are typically used where accent or decorative lighting effects are desired. E12 bulbs can come in different sizes, shapes, and types, including incandescent, CFL, and LED.