Abstract: The present invention teaches that a custom designed tool might serve as a marker cap for a standard size and diameter of marker such as a Sharpie® or Revmark® brand marker, along with an LED or low light LED or dim red LED or even infrared LED, and a hex drive socket which could then be used with an appropriate size of hex bit (such as a BITHEX™ tool head) for the exact size of adjustment screw heads found on any particular laser gun aiming device. The LED serves to light the laser aiming device screw head and the hex bit tool head, and in embodiments may be quite dim or otherwise inconspicuous.