It is one common bulb holder which thread specification diameter is 27mm. Easy to install, you just need to fix wire correctly to the positive or negative pole and then assemble all the parts together. Install the socket and decorate room with families according to your thoughts. Features - Color: Gold Bronze. - Material: Aluminum. - Size: 5.00X5.00X8.50cm/1.97X1.97X3.34inch. - Heat-resistant Temperature: 210 degree centigrade. - These E27 light sockets are medium base sockets and fit all E27 light bulbs. - Can be used for most light bulb lamp. Easy to Install, your room will be filled with great lighting. - Especially vintage Edison lamps, suitable for decorative DIY pendant lights. - Easy to install. Applicable for standard light bulb with E27 lamp base. - When using the electrical connector, connect and lamp directly, then fix it with a vice. Package list: 2 x light sockets