a markerlight drone can be attached to the unit(vehicle, squad... etc.) its also standard on all pathfinder carbines. after the system has hit its target you(counts as shooting) put markerlight tokens by the unit 'tagged'. after you are done with all marker light shots you can then use the tokens for things, a +1 to BS up to BS 5, fire a seeker missile at BS 5 from a nearby vehicle for 1 token, get minuses to ldr for pinning tests for the unit tagged and -1 for each counter to your opponents cover saves. but between oh... jump up onto a hill in the movement phase marker light with drones (cause drones marker lights are considered twin linked yay for the re-roll misses) on intended target(within 36" for the system) then nail them with ballistic skill 5 shots and then hop back down onto the other side of the hill where no one can see you in the assault phase because of the jet pack rule. unless of course you wiped out said unit... then go find next unit to target.