PCB mounted DC power jack connectors are small cylindrical connectors with a central metal pin. They come in a variety of sizes to suit:

A range of power ratings
Orientation on the PCB - Vertical and Horizontal
PCB mount type - Thru Hole and SMT

These connectors are normally used in an input/output function on handheld equipment. Mounted on a PCB and through a panel cut out to allow connection to a power supply.
The jack is mounted on the product to be powered, the mating cylindrical plug (not supplied by GCT) is normally mounted on a cable assembly connected to a power supply.
Jacks contain a normally closed contact, which can be used to disconnect internal batteries whenever the power supply is connected, avoiding the risk of battery leakage or explosion posed by incorrect recharging of the batteries.
Sometimes this connector system is known as 'coaxial power connectors', 'barrel connectors', or 'tip connectors'.