This vintage tube and tube socket from Philco is the 12AZ7 edition. It provides an easy and affordable option for replacement part needs on a radio or television set or can be purchased as a vintage collector's item as it is a great addition to any antique or technology connection. The tube socket functions like an electrical socket into which vacuum tubes or valves are plugged. The tube socket holds the valve in place and provides terminals, which can be soldered into the circuit, for each of the pins. Sockets, like this variation, are designed to allow tubes to be plugged in only one orientation. In the old days, they were used in all electronic equipment to allow tubes, which failed relatively frequently, to be quickly tested and replaced.