The Just Add Power 1-rack unit rack shelf (RS1U) provides an easy way to mount standalone Just Add Power units in a rack. Holds up to 13 Just Add Power standalone units. Pre-cut slots with separating tabs for ventilation. Matte black finish. Keep organized use the Just Add Power RS1U to organize standalone 2G and 3G transmitters and receivers in a rack. Just Add Power units in the RS1U will take up between 3 to 5 RU of space.