This generator is a simple and compact VGA/SVGA/XGA color generator. It is a unique, practical product for testing and adjusting. VGA/SVGA/XGA display devices such as monitors, projectors, etc. In the four most common VGA resolution modes - 640x480, 800x600, 1024x768 and 1280x1024. Whenever power is applied, and one of the resolution select buttons is pressed, it outputs a color pattern through the 15 pin D connector. It is powered by a 9V battery(6F22ND). Need to remove the battery if using external AC adapter(7.5~9.0V). This generator does not include AC adapter