DC power adapter,Wide used for external power source and on-board transformer. Connector Size - 5.5mm x 2.1mm Male to 5.5mm x2.5mm Female Connector tip DC Connector tip good connector, convenience and compact for your daily usage. Perfect for making a cable to a desired length or replacing a broken connector. Male to Female DC Jack connector, easier for camera installation.great item for small electronics projects and CCTV applications.