The small Edison screw cap is typically used as a replacement for the E26 screw cap in the LED bulb design. It has a diameter of 14 mm and is particularly utilized in Great Britain and Europe. This cap isn't to be confused with the 26 mm "E26," which is meant for the 120V US market. The bayonet cap, also called BC or B22D, has been used for several years as an alternate to the pin-push design for LED lamps.

With a diameter of 14 mm, the small Edison screw bulb could also be a smaller version of the E27. The R50 bulb is provided with a diameter of 14.5 mm and is embedded with an output voltage of 120V and an influence of 1.2 watts.