The RadioShack Size M (5.5 x 2.1mm) Panel-Mount DC Power Jack 274-1563 is a DC power jack designed for panel mounting. With a compact size of 5.5 x 2.1mm and a RadioShack brand, this jack is suitable for various consumer electronics and power cable applications. The panel-mount feature allows for easy integration into devices or systems requiring a power jack with this specific size and model number.