Abstract: Novel adjustable panels, systems, and methods are provided. In one aspect, an adjustable panel system can include a first panel, a second panel, and a third panel. The first panel and the second panel can be adjustable to a plurality of adjusted positions with respect to each other in a plurality of fixed increments. The third panel can be adjustably movable with respect to the second panel in increments smaller than the fixed increments. In one aspect, the panels, systems, and methods can be used to provide a portion of a security cage used to house sensitive electrical equipment.