They shoot magnesium impregnated rounds. When they hit, they go off like a flashbulb. I flew a night close air support with them once. They find the target with their IR TV and light it up with the "sparkling". We roll in hot aiming at the sparkling until co-altitude, then they stop so we don't get friendly fire. For a few seconds (which seems like eternity) we are diving into complete black holding our last aim position until bomb release, then we can pull out and find stars. The other cool thing is they record the video, and during debrief you can see the target, the sparkling, and your bomb hits on the tape.