An E26 bulb is a type of light bulb that has a cap or base that allows for both electrical and mechanical contact. The letter "E" in E26 refers to Edison Screw, which is the most standard of lamp bases, while the numerical "26" refers to its diameter in millimeters (approximately 1 inch) . E26 is also commonly referred to as a Medium Edison Screw (MES) . The E26 designation only refers to the bulbs base or contact point with the lamp holder, and it does not provide any information about the shape of the bulb. E26 bulbs are some of the most widely used lamp bases in North America and Japan, and other countries that commonly use 120V AC. Although previously they were most commonly used with incandescent lamps, fluorescent CFL lamps and LED lamps have also continued to adopt the E26 lamp base. You can recognize an E26 bulb by looking at the bottom, or non-light emitting side of the bulb. If you see a metallic base with screw threads, approximately 1 inch in diameter, you most likely have an E26 bulb[[2]](https://www.creative-cables.us/blog/194_light-bulb-sockets-what-does...