US Night Vision Guardian IR Mockingbird MarkersThe US Night Vision Guardian IR Mockingbird Marker is a programable marker that have impressives functions in the field using any IR light source. The recording time of this marker is 20 seconds, enabling it to copy most IR signatures with ease, including one from another Guardian Mockingbird. Another excellent feature is the Reverse Polarity Program Switching. This system assures that its programming and recording feature will only activate in one