Circular connector A circular connector designates a generic type of electrical connector whose plugs and sockets are cylindrical. Depending on voltage and current requirements, a large number of pins are available on the connector. A notch or mark is often on the connector, which makes it easy to align the two parts to avoid damaging or deforming the pins. They are usually made of metal and plastic. The locking mechanism can take the form of a collar, a rotary latch or a thread to ensure a perfect connection. They are commonly found in rugged applications as they will not be damaged or deteriorate other components. It is much easier to isolate a circular ring from the effects of the environment (compared to other forms). If there are space constraints, the circular connectors are not necessarily suitable because they can not be easily accommodated.