FORT INDIANTOWN GAP, PA--Leaders of the 42nd Infantry Division of the New York Army National Guard conduct a Rehearsal of Concept (ROC) drill at Fort Indiantown Gap Pennsylvania on Oct. 4 2017 as the division moves into the first day of its Warfighter exercise. Leaders talked through key mission points to ensure that leaders at all levels have a shared operational concept. Warfighter tests the ability of division and brigade levels to conduct staff functions.