Dimensions: the outside diameter measures about 6 cm, inside diameter is approx. 2.9 cm and height is approx. 0.5 cm Converts European and Continental lamp shades to British lamp holder size Warm notes: the lampshade is larger, it is not suitable for resting the smaller light bulb; Install the reducer ring can help you use a small bulb The white metal lamp shade reducing ring can help the unsuitable lamp shades. the lamp ring is made of durable quality metal, fits on lampshade better than plastic ones, durable to use and last for a long time . These lamp shade reducer rings can help you and meet your needs, so you don't worry about the lamp shape is too large., Manufacturer: DC Voltage