Oil lamp chimneys are used to cover and protect the flame of an oil lamp. The chimney serves several purposes: Protection: The chimney shields the flame from drafts and prevents it from being extinguished easily. This is especially important in outdoor settings or drafty indoor environments. Safety: By containing the flame within the glass chimney, the risk of fire hazards is reduced. It prevents sparks or embers from escaping and causing accidents. Enhanced Light: The shape and design of the chimney can help to concentrate and direct the light produced by the oil lamp, providing better illumination. Aesthetic Appeal: Chimneys often come in decorative designs, adding to the visual appeal of the oil lamp and enhancing the ambiance of the space in which it is used. Overall, oil lamp chimneys play a crucial role in the function, safety, and aesthetics of oil lamps. This chimney has a 2-5/8" base x 7-1/2" height x 3-1/2" bulge. This chimney fits the Rayo Chamber oil lamp. Do you have an oil lamp and need a replacement globe? We can help you out! Please check dimensions carefully, because these chimneys may fit other lanterns, too.Made from high-quality glass. Overall: 2-5/8" Outer Diameter Base x 7-1/2" High, Bulge: 3-1/2", Top OD: 1-5/8" . Note: Measurements are approximate and can vary slightly.