Great Value LED Light Bulbs are a great option for their cost and energy efficiency. A 3-way LED bulb is a type of light bulb that offers three different brightness levels in a single bulb. To use this feature, you need a 3-way light socket. A 3-way light socket is a common and traditional type of lamp socket that allows you to use a 3-way light bulb, which has two filaments that can produce three different brightness levels: low, medium, and high. A 3-way light socket has three electrical contacts: one for the metal tab at the bottom of the bulb, one for the small ring-shaped contact off-center in the bottom of the bulb, and one for the metal shell of the bulb. By turning the switch on the socket, you can control which filament or combination of filaments receives power and you can choose between low, medium, or high brightness levels. Comes with E26 standard medium base.