Searchlight

Each time a model from your army makes a ranged attack that targets an enemy unit that is within 9" of and visible to any Searchlights from your army, re-roll a Hit of 1 and, if the model making that attack is a Sentry Gun, add 1 to the Hit roll as well.

This model is a terrain feature and counts as a Wall.

In the Create the Battlefield and Place Objective Markers step, set this terrain feature up in one of the Searchlight positions (marked D2 on the mission map) that does not already contain a Searchlight.