E27 is one of the most common light bulb sizes on the market. It refers to the diameter of the light bulb's thread. A 27 mm thread is screwed into the lamp socket.
Many smart light bulbs have an E27 thread and therefore fit into most lamp sockets in your home. Various versions are available, such as E27 bulbs with cold and warm white light and E27 bulbs with changeable light color .
Fun fact: The E stands for Thomas Edison, the developer of the thread.
